-
A two-step Rayleigh-Schrödinger Brillouin-Wigner approach to transition energies Electron. Struct. Pub Date : 2024-02-23 Loris Delafosse, Amr Hussein, Saad Yalouz, Vincent Robert
Perturbative methods are attractive to describe the electronic structure of molecular systems because of their low-computational cost and systematically improvable character. In this work, a two-step perturbative approach is introduced combining multi-state Rayleigh-Schrödinger (effective Hamiltonian theory) and state-specific Brillouin-Wigner schemes to treat degenerate configurations and yield an
-
Hydrostatic pressure-induced anomalous hall effect in Co2FeSi semimetal Electron. Struct. Pub Date : 2024-02-15 Jyotirmoy Sau, Debanand Sa, Manoranjan Kumar
The Weyl points and nodal line emerge in the momentum space due to symmetry protected state in topological semimetal materials and these materials hold significance due to their unusual anomalous transport properties. In this manuscript, we study the topological properties of the electronic band structure of a half-metallic ferromagnet Co2FeSi employing the ab-initio density functional theory method
-
Perturbative variational quantum algorithms for material simulations Electron. Struct. Pub Date : 2024-02-13 Jie Liu, Zhenyu Li, Jinlong Yang
Reducing circuit depth is essential for implementing quantum simulations of electronic structure on near-term quantum devices. In this work, we propose a variational quantum eigensolver (VQE) based perturbation theory (PT) algorithm to accurately simulate electron correlation of periodic materials with shallow ansatz circuits, which are generated from adaptive derivative-assembled pseudo-trotter or
-
Point-like vacancies in two-dimensional transition metal dichalcogenides Electron. Struct. Pub Date : 2024-02-08 Sibel Özcan, Aurelio Gallardo, Blanca Biel
This study explores the realm of two-dimensional transition metal dichalcogenides (TMDs), examining some of the most prevalent defects. Employing density functional theory, we scrutinize three common defect types across four extensively studied TMDs: MoS2, MoSe2, WS2, and WSe2. Our investigation spans the energetics of these defects, unveiling the most stable ones, and unraveling the alterations in
-
Integrating subsystem embedding subalgebras and coupled cluster Green’s function: a theoretical foundation for quantum embedding in excitation manifold Electron. Struct. Pub Date : 2024-02-01 Bo Peng, Karol Kowalski
In this study, we introduce a novel approach to coupled-cluster Green’s function (CCGF) embedding by seamlessly integrating conventional CCGF theory with the state-of-the-art sub-system embedding sub-algebras coupled cluster (SES-CC) formalism. This integration focuses primarily on delineating the characteristics of the sub-system and the corresponding segments of the Green’s function, defined explicitly
-
A superhard sp2–sp3 hybridized orthorhombic carbon allotrope with conductive property under extreme pressure Electron. Struct. Pub Date : 2024-01-31 Neetik Mukherjee, Gaurav Shukla, Ashwani K Tiwari
Superhard materials with conductive properties are extremely important. They have potential applications in multifunctional devices under extreme natural conditions. Here we present a superhard and conductive sp2–sp3 mixed hybrid carbon allotrope through Density functional theory calculations. The proposed carbon phase contains 36 atoms in an orthorhombic unit cell with Pmmm symmetry. In present structure
-
Study on the mechanism of oxygen atom-related non-covalent interactions on the structure of non-fused ring acceptor molecules and their optoelectronic properties Electron. Struct. Pub Date : 2024-01-24 Miao Wang, Lei Wang, Huanhuan Gao, Jin Li, Zhao Liu, Haiyang Song
Non-covalent interactions play a crucial role in regulating the molecular conformation and optoelectronic properties of the acceptor. In this paper, hydroxyl groups of different positions and numbers are inserted on the original non-fused ring acceptor molecule W0. Thus, eight novel molecules were designed. Density functional theory (DFT) and time-dependent DFT (TD-DFT) are used to investigate the
-
Phonons from density-functional perturbation theory using the all-electron full-potential linearized augmented plane-wave method FLEUR * * Dedicated to the memory of Henry Krakauer (1947–2023). Electron. Struct. Pub Date : 2024-01-04 Christian-Roman Gerhorst, Alexander Neukirchen, Daniel A Klüppelberg, Gustav Bihlmayer, Markus Betzinger, Gregor Michalicek, Daniel Wortmann, Stefan Blügel
Phonons are quantized vibrations of a crystal lattice that play a crucial role in understanding many properties of solids. Density functional theory provides a state-of-the-art computational approach to lattice vibrations from first-principles. We present a successful software implementation for calculating phonons in the harmonic approximation, employing density-functional perturbation theory within
-
Rare earth (Tm, Y, Gd, and Eu) doped ZnS monolayer: a comparative first-principles study Electron. Struct. Pub Date : 2024-01-04 Adil Es-Smairi, Nejma Fazouan, E Maskar, Ibrahim Bziz, Mohammed Sabil, Ayan Banik, D P Rai
In this current study, we used the density functional theory method to examine the physical properties of ZnS nanosheets doped with Tm, Y, Gd, and Eu at a concentration of 6.25%. The non-magnetic phase is energetically stable when doped with Y and Tm. However, the ferromagnetic state is thermodynamically stable when doped with Eu and Gd, show negative formation energy. The optimised structure is a
-
Three-dimensional electronic structure of the superconductor Sn4Sb3 by angle-resolved photoemission spectroscopy Electron. Struct. Pub Date : 2024-01-04 Pengfei Ding, Xiaoxiao Man, Qingxin Liu, Huan Ma, Bin Liu, Zhi Ren, Kai Liu, Shancai Wang
The layered material Sn4Sb3 exhibits superconductivity with Tc∼ 1.47 K and is proposed to be a topological superconductor candidate. In this study, we investigate the electronic structure of Sn4Sb3 using angle-resolved photoemission spectroscopy and density functional theory (DFT) calculations. Despite its layered structure, the band structure of Sn4Sb3 shows strong kz dependence, leading to the formation
-
B and N substitutional co-doping in 7AGNRs Electron. Struct. Pub Date : 2023-12-27 Rodrigo E Menchón, Iñigo Delgado-Enales, Daniel Sánchez-Portal, Aran Garcia-Lekue
On-surface synthesis of graphene nanoribbons enables engineering their electronic and magnetic properties, which sensitively depend on their precise bonding structure, morphology and chemical composition. Here, we investigate nitrogen and boron co-doping in order to better understand the effects of simultaneous chemical substitution in sites along the backbone of 7AGNRs. In a comparative analysis with
-
Optical properties of charged defects in monolayer MoS2 Electron. Struct. Pub Date : 2023-11-27 Martik Aghajanian, Arash A Mostofi, Johannes Lischner
We present theoretical calculations of the optical spectrum of monolayer MoS2 with a charged defect. In particular, we solve the Bethe–Salpeter equation based on an atomistic tight-binding model of the MoS2 electronic structure which allows calculations for large supercells. The defect is modelled as a point charge whose potential is screened by the MoS2 electrons. We find that the defect gives rise
-
Topological nonsymmorphic insulator versus Dirac semimetal in KZnBi Electron. Struct. Pub Date : 2023-11-27 Rahul Verma, Bikash Patra, Bahadur Singh
KZnBi was discovered recently as a new three-dimensional Dirac semimetal with a pair of bulk Dirac fermions in contrast to the Z2 trivial insulator reported earlier. In order to address this discrepancy, we have performed electronic structure and topological state analysis of KZnBi using the local, semilocal, and hybrid exchange-correlation (XC) functionals within the density functional theory framework
-
Electronic properties of two dimensional PtSSe/SrTiO3 Janus Van der Waals heterostructures Electron. Struct. Pub Date : 2023-11-24 Arwa Albar, Anjana E Sudheer, D Murali, S Assa Aravindh
The structural stability and electronic properties of two dimensional PtSSe/SrTiO3 Janus heterostructures were investigated using density functional theory calculations, considering both S and Se terminations into account. Ab-initio thermodynamics simulations revealed that the heterostructure formed with Se/Ti interface termination is more stable with an energy difference of 1.53 eV than the S/Ti termination
-
Impact of the Ce 4f states in the electronic structure of the intermediate-valence superconductor CeIr3 Electron. Struct. Pub Date : 2023-11-16 Shin-ichi Fujimori, Ikuto Kawasaki, Yukiharu Takeda, Hiroshi Yamagami, Norimasa Sasabe, Yoshiki J Sato, Ai Nakamura, Yusei Shimizu, Arvind Maurya, Yoshiya Homma, Dexin Li, Fuminori Honda, Dai Aoki
The electronic structure of the f-based superconductor CeIr3 was studied by photoelectron spectroscopy. The energy distribution of the Ce 4f states were revealed by the Ce 3d−4f resonant photoelectron spectroscopy. The Ce 4f states were mostly distributed in the vicinity of the Fermi energy, suggesting the itinerant character of the Ce 4f states. The contribution of the Ce 4f states to the density
-
Electronic structure, optical properties and defect induced half-metallic ferromagnetism in kagome Cs2Ni3S4 Electron. Struct. Pub Date : 2023-11-16 Gang Bahadur Acharya, Bishnu Prasad Belbase, Madhav Prasad Ghimire
Recent research focuses on electronic structure of kagome materials due to their fascinating properties such as topological insulators, Dirac semimetals, and topological superconductors. Materials with sizable electronic band gap are found to play vital role in device applications. Here, by means of density functional theory calculations, we study the electronic and optical properties of ternary transition
-
Quantum eigenvector continuation for chemistry applications Electron. Struct. Pub Date : 2023-11-10 Carlos Mejuto-Zaera, Alexander F Kemper
A typical task for classical and quantum computing in chemistry is finding a potential energy surface (PES) along a reaction coordinate, which involves solving the quantum chemistry problem for many points along the reaction path. Developing algorithms to accomplish this task on quantum computers has been an active area of development, yet finding all the relevant eigenstates along the reaction coordinate
-
Optimization strategies in WAHTOR algorithm for quantum computing empirical ansatz: a comparative study Electron. Struct. Pub Date : 2023-10-27 Leonardo Ratini, Chiara Capecci, Leonardo Guidoni
By exploiting the invariance of the molecular Hamiltonian by a unitary transformation of the orbitals it is possible to significantly shorter the depth of the variational circuit in the variational quantum eigensolver (VQE) algorithm by using the wavefunction adapted Hamiltonian through orbital rotation (WAHTOR) algorithm. This work introduces a non-adiabatic version of the WAHTOR algorithm and compares
-
Graphene/aluminum oxide interfaces for nanoelectronic devices Electron. Struct. Pub Date : 2023-10-19 V-B Vu, J L Bubendorff, L D N Mouafo, S Latil, A Zaarour, J-F Dayen, L Simon, Y J Dappe
In this work, we study theoretically and experimentally graphene/aluminum oxide interfaces as 0D/2D interfaces for quantum electronics as the nature of the interface is of paramount importance to understand the quantum transport mechanism. Indeed, the electronic transport is driven either by a channel arising from a strong hybridization at the interface, or by tunneling across a van der Waals interface
-
Computational workflow for steric assessment using the electric field-derived size Electron. Struct. Pub Date : 2023-10-16 Austin M Mroz, Lukas Turcani, Kim E Jelfs
Molecular structure plays an important role in the selectivity and performance of catalysts. Understanding the impact of structural differences on catalyst performance via quantitative structure-selectivity relationships is key to developing high-performing catalytic systems. There are several methods that have been introduced to quantify steric contributions, including Tolman cone angles, Charton
-
Impact of electronic correlations on high-pressure iron: insights from time-dependent density functional theory Electron. Struct. Pub Date : 2023-10-06 K Ramakrishna, M Lokamani, A Baczewski, J Vorberger, A Cangi
We present a comprehensive investigation of the electrical and thermal conductivity of iron under high pressures at ambient temperature, employing the real-time formulation of time-dependent density functional theory (RT-TDDFT). Specifically, we examine the influence of a Hubbard correction (+U) to account for strong electron correlations. Our calculations based on RT-TDDFT demonstrate that the evaluated
-
Sample degradation and beam-induced damage in (synchrotron-based) electronic structure experiments Electron. Struct. Pub Date : 2023-10-06 Antje Vollmer, Raphael Schlesinger, Johannes Frisch
Synchrotron radiation-based methods, in particular photoemission spectroscopy, are very powerful tools for studying the electronic, chemical, and structural properties of materials and combinations of materials. Numerous experimental studies have been performed in the last decades using synchrotron radiation in physics, chemistry, material science, biology, medicine, and more. However, the advantage
-
Second response theory: a theoretical formalism for the propagation of quantum superpositions Electron. Struct. Pub Date : 2023-09-29 Martín A Mosquera
The propagation of general electronic quantum states provides information of the interaction of molecular systems with external driving fields. These can also offer understandings regarding non-adiabatic quantum phenomena. Well established methods focus mainly on propagating a quantum system that is initially described exclusively by the ground state wavefunction. In this work, we expand a previously
-
Progress in the studies of electronic and magnetic properties of layered MPX3 materials (M: transition metal, X: chalcogen) Electron. Struct. Pub Date : 2023-09-29 Yuriy Dedkov, Yefei Guo, Elena Voloshina
The recent progress in the studies of 2D materials placed in front many experimental and theoretical works on the interesting class of materials, the so-called transition metal phosphorus trichalcogenides with structural formula MPX3 (M: transition metal, X: chalcogen). Here, the diversity in the M/X combination opens the possibility to tune the electronic and magnetic properties of these materials
-
Impurity atom configurations in diamond and their visibility via scanning transmission electron microscopy imaging Electron. Struct. Pub Date : 2023-09-28 D Propst, J Kotakoski, E H Åhlgren
Dispersed impurities in diamond present a flourishing platform for research in quantum informatics, spintronics and single phonon emitters. Based on the vast pool of experimental and theoretical work describing impurity atoms in diamond, we review the configurations by the chemical element discussing the relevant atomic configurations and most important properties. Dopant structures expand from single
-
Bayesian phase difference estimation algorithm for direct calculation of fine structure splitting: accelerated simulation of relativistic and quantum many-body effects Electron. Struct. Pub Date : 2023-09-25 Kenji Sugisaki, V S Prasannaa, Satoshi Ohshima, Takahiro Katagiri, Yuji Mochizuki, B K Sahoo, B P Das
Despite rapid progress in the development of quantum algorithms in quantum computing as well as numerical simulation methods in classical computing for atomic and molecular applications, no systematic and comprehensive electronic structure study of atomic systems that covers almost all of the elements in the periodic table using a single quantum algorithm has been reported. In this work, we address
-
Ab initio calculation of electron-phonon linewidths and molecular dynamics with electronic friction at metal surfaces with numeric atom-centred orbitals Electron. Struct. Pub Date : 2023-09-21 Connor L Box, Wojciech G Stark, Reinhard J Maurer
Molecular motion at metallic surfaces is affected by nonadiabatic effects and electron-phonon coupling. The ensuing energy dissipation and dynamical steering effects are not captured by classical molecular dynamics simulations, but can be described with the molecular dynamics with electronic friction method and linear response calculations based on density functional theory. Herein, we present an implementation
-
Cutoff phenomenon and entropic uncertainty for random quantum circuits Electron. Struct. Pub Date : 2023-09-01 Sangchul Oh, Sabre Kais
How fast a state of a system converges to a stationary state is one of the fundamental questions in science. Some Markov chains and random walks on finite groups are known to exhibit the non-asymptotic convergence to a stationary distribution, called the cutoff phenomenon. Here, we examine how quickly a random quantum circuit could transform a quantum state to a Haar-measure random quantum state. We
-
Excitons in organic materials: revisiting old concepts with new insights Electron. Struct. Pub Date : 2023-09-01 Ana M Valencia, Daniel Bischof, Sebastian Anhäuser, Marc Zeplichal, Andreas Terfort, Gregor Witte, Caterina Cocchi
The development of advanced experimental and theoretical methods for the characterization of excitations in materials enables revisiting established concepts that are sometimes misleadingly transferred from one field to another without the necessary disclaimers. This is precisely the situation that occurs for excitons in organic materials: different states of matter and peculiarities related to their
-
Optical excitations in 2D semiconductors Electron. Struct. Pub Date : 2023-08-10 Thorsten Deilmann, Michael Rohlfing, Kristian Sommer Thygesen
Two-dimensional (2D) materials have revealed many fascinating physical and chemical properties. Due to the quantum confinement and enhanced many-body effects especially the optical properties are altered compared to their bulk counterparts. The optics of 2D materials can easily be modified by various means, e.g. the substrate, doping, strain, stacking, electric or magnetic fields. In this review we
-
Multistate multiscale docking study of the hydrolysis of toxic nerve agents by phosphotriesterase Electron. Struct. Pub Date : 2023-08-08 Prashant Kumar Gupta, Naziha Tarannam, Shani Zev, Dan Thomas Major
The G- and V-type nerve agents are among the most toxic compounds known, where inhalation of a few mg could cause potential death. Over the years wild-type phosphotriesterase (PTE) has gained much attention due to its capability of detoxifying these deadly compounds. The underlying mechanism proceeds via a hydroxyl attack on the P or C centers of the organophosphate nerve agents followed by the departure
-
Accelerating variational quantum eigensolver convergence using parameter transfer Electron. Struct. Pub Date : 2023-08-04 Mårten Skogh, Oskar Leinonen, Phalgun Lolur, Martin Rahm
One impediment to the useful application of variational quantum algorithms in quantum chemistry is slow convergence with large numbers of classical optimization parameters. In this work, we evaluate a quantum computational warm-start approach for potential energy surface calculations. Our approach, which is inspired by conventional computational methods, is evaluated using simulations of the variational
-
Prospects required for future light-source facilities: a case of UVSOR synchrotron facility Electron. Struct. Pub Date : 2023-07-14 S Kera, F Matsui, K Tanaka, Y Taira, T Araki, T Ohigashi, H Iwayama, M Fujimoto, H Matsuda, E Salehi, M Katoh
The synchrotron radiation facility is a large-scale public infrastructure that provides advanced light sources and is used for various academic research and application development. For 40 years, UVSOR Synchrotron Facility has been leading the field as a facility that has developed and utilized cutting-edge light source technology in the low-photon-energy regime. The next UVSOR aims to establish a
-
On validity and limits of deducing the degree of charge transfer from shifts of cyano vibrations Electron. Struct. Pub Date : 2023-07-14 Melissa Berteau-Rainville, Emanuele Orgiu, Ingo Salzmann
Understanding the p-doping of organic semiconductors often relies on spectroscopic fingerprints of cyano vibrations, which strongly depend on the charge state of the dopant molecule following intermolecular charge transfer. Interpreting these vibrations can be difficult as a number of other factors can impact them. Here, we formalize the assumptions behind the determination of molecular charge from
-
Measuring exciton-phonon coupling in semiconductor nanocrystals Electron. Struct. Pub Date : 2023-07-05 Albert Liu, Diogo B Almeida, Steven T Cundiff, Lazaro A Padilha
At low excitation density, the dynamics of excitons in semiconductor nanocrystals are largely dictated by their interactions with the underlying atomic lattice. This exciton-phonon coupling (EPC) is responsible, for example, for absorption and luminescence linewidths at elevated temperatures, relaxation processes following optical excitation, and even degradation of quantum coherent applications. Characterizing
-
Understanding the role of oxygen-vacancy defects in Cu2O(111) from first-principle calculations Electron. Struct. Pub Date : 2023-07-04 Nanchen Dongfang, Yasmine S Al-Hamdani, Marcella Iannuzzi
The presence of defects, such as copper and oxygen vacancies, in cuprous oxide films determines their characteristic carrier conductivity and consequently their application as semiconducting systems. There are still open questions on the induced electronic re-distribution, including the formation of polarons. Indeed, to accurately reproduce the structural and electronic properties at the cuprous oxide
-
Optical spectra of EGFR inhibitor AG-1478 for benchmarking DFT functionals Electron. Struct. Pub Date : 2023-07-03 Sallam Alagawani, Vladislav Vasilyev, Feng Wang
Optical spectroscopy (UV–vis and fluorescence spectroscopy) is sensitive to the chemical environment and conformation of fluorophores and therefore, serves as an ideal probe for the conformation and solvent responses. Tyrosine kinase inhibitors (TKI) such as AG-1478 of epidermal growth factor receptor when containing a quinazolinamine scaffold are fluorophores. It is, however, very important to benchmark
-
AiiDA-defects: an automated and fully reproducible workflow for the complete characterization of defect chemistry in functional materials Electron. Struct. Pub Date : 2023-06-30 Sokseiha Muy, Conrad Johnston, Nicola Marzari
Functional materials that enable many technological applications in our everyday lives owe their unique properties to defects that are carefully engineered and incorporated into these materials during processing. However, optimizing and characterizing these defects is very challenging in practice, making computational modelling an indispensable complementary tool. We have developed an automated workflow
-
Anomalous delocalization of resonant states in graphene & the vacancy magnetic moment Electron. Struct. Pub Date : 2023-06-30 Mirko Leccese, Rocco Martinazzo
Carbon atom vacancies in graphene give rise to a local magnetic moment of σ+π origin, whose magnitude is yet uncertain and debated. Partial quenching of π magnetism has been ubiquitously reported in periodic first principles calculations, with magnetic moments scattered in the range 1.0–2.0 µ B, slowly converging to the lower or the upper end, depending on how the diluted limit is approached. By contrast
-
Optical properties of twisted bilayer graphene with magnetic defects Electron. Struct. Pub Date : 2023-06-16 Nikita V Natalin, Evgeny V Kundelev, Ivan D Rukhlenko, Nikita V Tepliakov
Even when fabricated under ideal conditions twisted bilayer graphene (TBG) inevitably contains various defects which may significantly affect its physical properties. Here we comprehensively analyze the impact of typical point defects, represented by adsorbed hydrogen atoms, on the electronic and optical properties of TBG. It is shown using self-consistent tight-binding Hamiltonians that such point
-
Impact of electron correlations on the k-resolved electronic structure of PdCrO2 revealed by Compton scattering Electron. Struct. Pub Date : 2023-05-23 A D N James, D Billington, S B Dugdale
Delafossite PdCrO2 is an intriguing material which displays nearly-free electron and Mott insulating behaviour in different layers. Both angle-resolved photoemission spectroscopy (ARPES) and Compton scattering measurements have established a hexagonal Fermi surface in the material’s paramagnetic phase. However, the Compton experiment detected an additional structure in the projected occupancy which
-
Thermokinetics of point defects in α-Fe2O3 Electron. Struct. Pub Date : 2023-05-19 Amitava Banerjee, Edward F Holby, Aaron A Kohnert, Shivani Srivastava, Mark Asta, Blas P Uberuaga
Point defect formation and migration in oxides governs a wide range of phenomena from corrosion kinetics and radiation damage evolution to electronic properties. In this study, we examine the thermodynamics and kinetics of anion and cation point defects using density functional theory in hematite ( α -Fe2O3), an important iron oxide highly relevant in both corrosion of steels and water-splitting applications
-
Mapping charge-transfer excitations in Bacteriochlorophyll dimers from first principles Electron. Struct. Pub Date : 2023-05-16 Zohreh Hashemi, Matthias Knodt, Mario R G Marques, Linn Leppert
Photoinduced charge-transfer excitations are key to understand the primary processes of natural photosynthesis and for designing photovoltaic and photocatalytic devices. In this paper, we use Bacteriochlorophyll dimers extracted from the light harvesting apparatus and reaction center of a photosynthetic purple bacterium as model systems to study such excitations using first-principles numerical simulation
-
A high-level quantum chemical study of the thermodynamics associated with chlorine transfer between N-chlorinated nucleobases Electron. Struct. Pub Date : 2023-05-12 Robert J O’Reilly, Amir Karton
The relative free energies of the isomers formed upon N-chlorination of each nitrogen atom within the DNA nucleobases (adenine, guanine, and thymine) have been obtained using the high-level G4(MP2) composite ab initio method (the free energies of the N-chlorinated isomers of cytosine have been reported at the same level of theory previously). Having identified the lowest energy N-chlorinated derivatives
-
A deep investigation of NiO and MnO through the first principle calculations and Monte Carlo simulations Electron. Struct. Pub Date : 2023-04-28 Mojtaba Alaei, Homa Karimi
In this study, we use Hubbard-corrected density functional theory (DFT+U) to derive spin model Hamiltonians consisting of Heisenberg exchange interactions up to the fourth nearest neighbors and bi-quadratic interactions. We map the DFT+U results of several magnetic configurations to the Heisenberg spin model Hamiltonian to estimate Heisenberg exchanges. We demonstrate that the number of magnetic configurations
-
Extended-charge-transfer excitations in crystalline non-fullerene acceptors Electron. Struct. Pub Date : 2023-04-25 Zhixing Liu, Chunfeng Zhang
In organic solar cells with non-fullerene acceptors (NFAs), an intra-moiety excited state, originating from intermolecular interactions in the acceptor domain, acts as a key immediate for charge separation. However, the nature of the intra-moiety state remains elusive. Here, we employ a model Hamiltonian with parameters derived from a model system of Y6 crystal to study the nature of low-lying excited
-
An efficient implementation of analytical nuclear gradients for linear-response time-dependent density functional theory in the plane wave basis Electron. Struct. Pub Date : 2023-04-14 Jie Liu, Wei Hu, Jinlong Yang
We present an efficient implementation of the analytical nuclear gradient of linear-response time-dependent density functional theory (LR-TDDFT) with the frozen core approximation (FCA). This implementation is realized based on the Hutter’s formalism and the plane wave pseudopotential method. Numerical results demonstrate that the LR-TDDFT/FCA method using a small subset of Kohn–Sham occupied orbitals
-
Floquet engineering of magnetism in topological insulator thin films Electron. Struct. Pub Date : 2023-04-14 Xiaoyu Liu, Benshu Fan, Hannes Hübener, Umberto De Giovannini, Wenhui Duan, Angel Rubio, Peizhe Tang
Dynamic manipulation of magnetism in topological materials is demonstrated here via a Floquet engineering approach using circularly polarized light. Increasing the strength of the laser field, besides the expected topological phase transition (PT), the magnetically doped topological insulator thin film also undergoes a magnetic PT from ferromagnetism to paramagnetism, whose critical behavior strongly
-
Defects in WS2 monolayer calculated with a nonlocal functional: any difference from GGA? Electron. Struct. Pub Date : 2023-04-06 Daria Kieczka, Thomas Durrant, Katherine Milton, Kuan Eng Johnson Goh, Michel Bosman, Alexander Shluger
Density functional theory (DFT) with generalised gradient approximation (GGA) functionals is commonly used to predict defect properties in 2D transition metal dichalcogenides (TMDs). Since GGA functionals often underestimate band gaps of semiconductors and incorrectly describe the character of electron localisation in defects and their level positions within the band gap, it is important to assess
-
Multiple resonance induced thermally activated delayed fluorescence: effect of chemical modification Electron. Struct. Pub Date : 2023-04-03 Xiaopeng Wang, Siyu Gao, Aizhu Wang, Bo Wang, Noa Marom
Thermally activated delayed fluorescence (TADF) is the internal conversion of triplet excitons into singlet excitons via reverse intersystem crossing (RISC). It improves the efficiency of organic light-emitting diodes (OLED) by enabling the harvesting of nonradiative triplet excitons. Multiple resonance (MR) induced TADF chromophores exhibit an additional advantage of high color purity due to their
-
Density-potential inversion from Moreau–Yosida regularization Electron. Struct. Pub Date : 2023-03-31 Markus Penz, Mihály A Csirik, Andre Laestadius
For a quantum-mechanical many-electron system, given a density, the Zhao–Morrison–Parr method allows to compute the effective potential that yields precisely that density. In this work, we demonstrate how this and similar inversion procedures mathematically relate to the Moreau–Yosida regularization of density functionals on Banach spaces. It is shown that these inversion procedures can in fact be
-
Low-rank approximations to accelerate hybrid functional enabled real-time time-dependent density functional theory within plane waves Electron. Struct. Pub Date : 2023-03-24 Jielan Li, Lingyun Wan, Shizhe Jiao, Wei Hu, Jinlong Yang
Real-time time-dependent density functional theory (RT-TDDFT) is a powerful tool for predicting excited-state dynamics. Herein, we combine the adaptively compressed exchange (ACE) operator with interpolative separable density fitting (ISDF) algorithm to accelerate the hybrid functional calculations in RT-TDDFT (hybrid RT-TDDFT) dynamics simulations for molecular and periodic systems within plane waves
-
Decomposing Hofmeister effects on amino acid residues with symmetry adapted perturbation theory Electron. Struct. Pub Date : 2023-03-14 Kasimir P Gregory, Grant B Webber, Erica J Wanless, Alister J Page
Hofmeister effects, and more generally specific ion effects, are observed broadly in biological systems. However, there are many cases where the Hofmeister series might not be followed in complex biological systems, such as ion channels which can be highly specific to a particular ion. An understanding of how ions from the Hofmeister series interact with the proteinogenic amino acids will assist elucidation
-
Strain effect on the high T c superconductor YBa2Cu3O7: an ab initio study comparing bulk and monolayer models Electron. Struct. Pub Date : 2023-03-10 Carla Yelpo, Sofía Favre, Daniel Ariosa, Ricardo Faccio
In this work, the effect of strain on the vibrational and electronic properties of the YBa2Cu3O7 compound was studied through ab initio calculations. For this, two structural models were used: a bulk model and a surface model (a monolayer with CuO2 and BaO as the terminating layers). The phonon spectra was calculated for both structures under different levels of c axis strain. The most appreciable
-
From defect to effect: controlling electronic transport in chevron graphene nanoribbons Electron. Struct. Pub Date : 2023-03-06 Kristiāns Čerņevičs, Oleg V Yazyev
While bottom-up synthesis allows for precise control over the properties of graphene nanoribbons (GNRs), the use of certain precursor molecules can result in edge defects, such as missing benzene rings that resemble a ‘bite’. We investigate the adverse effect of the ‘bite’ defects on the electronic transport properties in three chevron-type GNRs and discover that the extent of scattering is governed
-
Floquet formulation of the dynamical Berry-phase approach to nonlinear optics in extended systems Electron. Struct. Pub Date : 2023-03-02 Ignacio M Alliati, Myrta Grüning
We present a Floquet scheme for the ab-initio calculation of nonlinear optical properties in extended systems. This entails a reformulation of the real-time approach based on the dynamical Berry-phase polarisation (Attaccalite and Grüning 2013 Phys. Rev. B 88 1–9) and retains the advantage of being non-perturbative in the electric field. The proposed method applies to periodically-driven Hamiltonians
-
Single-point spin Chern number in a supercell framework Electron. Struct. Pub Date : 2023-02-20 Roberta Favata, Antimo Marrazzo
We present an approach for the calculation of the Z2 topological invariant in non-crystalline two-dimensional quantum spin Hall insulators. While topological invariants were originally mathematically introduced for crystalline periodic systems, and crucially hinge on tracking the evolution of occupied states through the Brillouin zone, the introduction of disorder or dynamical effects can break the
-
Covalency modulation enables stable Na-rich layered oxide cathodes for Na-ion batteries Electron. Struct. Pub Date : 2023-02-17 Xi Zhou, Manling Ding, Chen Cheng, Xiao Xia, Haolv Hu, Yihao Shen, Stanislav Fedotov, Liang Zhang
As the analogs of Li-rich materials, Na-rich transition metal layered oxides are promising cathode materials for Na-ion batteries owing to their high theoretical capacity and energy density through cumulative cationic and anionic redox. However, most of the reported Na-rich cathode materials are mainly Ru- and Ir-based layered oxides, which limits the practical application. Herein, we report a Na-rich
-
High-resolution electronic and vibrational spectroscopy of small-to-medium sized molecules with ab initio potential energy surface Electron. Struct. Pub Date : 2023-02-14 Soumyadip Ray, Debasish Koner, Padmabati Mondal
Electronic and vibrational spectroscopic studies of molecules are of crucial importance to characterizing a molecule and detecting the molecular species in different environments. In this review article, we summarized some important theoretical methods to calculate high-resolution electronic spectra and ro-vibrational states for small molecular systems with the inclusion of vibronic and ro-vibrational
-
Inter-quintuple layer coupling and topological phase transitions in the chalcogenide topological insulators Electron. Struct. Pub Date : 2023-02-10 K Shirali, Shelton W A, I Vekhter
Driving quantum phase transitions in the 3D topological insulators offers pathways to tuning the topological states and their properties. We use DFT-based calculations to systematically investigate topological phase transitions in Bi2Se3, Sb2Se3, Bi2Te3 and Sb2Te3 by varying the c/a ratio of lattice constants. This ensures no net hydrostatic pressure under anisotropic stress and strain and allows a