Efficient algorithms for the calculation of minimum energy paths of magnetic transitions are implemented within the geodesic nudged elastic band (GNEB) approach. While an objective function is not available for GNEB and a traditional line search can, therefore, not be performed, the use of limited memory Broyden–Fletcher–Goldfarb–Shanno (LBFGS) and conjugate gradient algorithms in conjunction with

We report the first-principles DFT calculation of the electron–hole Lindhard response function of the (TMTSF) 2 PF 6 Bechgaard salt using the real triclinic low-temperature structure. The Lindhard response is found to change considerably with temperature. Near the 2 k F spin density wave (SDW) instability it has the shape of a broad triangular plateau as a result of the multiple nesting associated

The effect of doping metal ions in ferroelastic Pb 3 (PO 4 ) 2 (PPO) on the polar nature of domain boundaries (DBs) was investigated using a second harmonic generation (SHG) microscope. It has been already reported that (DBs) of non-doped PPO is SH active and polar. The present study reveals that DBs of Ca-doped and Mg-doped PPO show greatly enhanced SH activity. This indicates that doping by metal

In the past decade, many gas-phase spectroscopic investigations have focused on the understanding of the nature of weak interactions in model systems. Despite the fact that non-covalent interactions play a key role in several biological and technological processes, their characterization and interpretation are still far from being satisfactory. In this connection, integrated experimental and computational

The longitudinal magnetoresistance (MR) is assumed to be hardly realized as the Lorentz force does not work on electrons when the magnetic field is parallel to the current. However, in some cases, longitudinal MR becomes large, which exceeds the transverse MR. To solve this problem, we have investigated the longitudinal MR considering multivalley contributions based on the classical MR theory. We have

Using the Su–Schrieffer–Heeger Hamiltonian and exploiting the Green’s function method in the framework of the Landauer–Büttiker formalism, the topological and spin dependent electron transport properties of a trans polyacetylene molecule are studied. It is found that molecules with the intracell single carbon–carbon bonding and the even number of monomers in their chains have two edge states and possess

Single-layer FeSe films grown on SrTiO 3 , with the highest superconducting transition temperature ( T C ) among all the iron-based superconductors, serves as an ideal platform for studying the microscopic mechanisms of high- T C superconductivity. The significant role of interfacial coupling has been widely recognized, while the precise nature of the T C enhancement remains open. In this review, we

We derive an asymptotic model for wave propagation across a ferromagnetic film, neglecting anisotropy and damping, close to the ferromagnetic resonance. The resulting model is a nonlinear Schrödinger equation, which can be either focusing or defocussing, depending on the magnitude and direction of the external magnetic field. We use it to compute the nonlinear eigenmodes of standing spin waves, that

Doubling the perovskite cell (double perovskite) has been found to open new possibilities for engineering functional materials, magnetic materials in particular. This route should be applicable to the antiperovskite (aPV) class. In the pnictide based double aPV (2aPV) class introduced here magnetism is very rare, and we address them as new topological materials, possibly with thermoelectric interest

Anisotropy of bulk magnetic properties and magnetic structure studies of a Tb 2 Pd 2 In single crystal by means of bulk magnetization methods and neutron diffraction techniques confirmed the antiferromagnetic order below the Néel temperature 29.5 K. The collinear magnetic structure of Tb magnetic moments aligned along the tetragonal c -axis is characterized by a propagation vector k = (1/4, 1/4, 1/2)

We have studied correlational properties of quasi-one-dimensional electron gas at finite temperature T by incorporating the dynamics of electron correlations within the quantum version of the self-consistent mean-field approach of Singwi, Tosi, Land, and Sjölander. Static structure factor, pair-correlation function, static density susceptibility, excess kinetic energy, and free correlation energy are

In this work a derivation of the effective interactions between two rotated graphene layers inside a microcavity is obtained. Assuming an electromagnetic wave clockwise-polarized, propagating along the z -axis and applying the Schrieffer–Wolff transformation, an explicit interaction between electrons in different graphene layers is obtained, where the interaction strength depends on the distance between

Recently synthesized two-dimensional graphene-like material referred to as graphenylene is a semiconductor with a narrow direct bandgap that holds great promise for nanoelectronic applications. The significant bandgap increase can be provided by the strain applied to graphenylene crystal lattice or by using nanoribbons instead of extended layers. In this paper, we present the systematic study of the

The manipulation of magnetism by electrical means is one of the most intensely pursued research topics of recent times aiming at the development of efficient and low-energy consumption devices in spintronics, microelectronics and bioelectronics. Herein, we successfully tuned the saturated magnetization of Fe3O4 by a supercapacitor. Through increasing the surface area of magnetic particles and activation

Amorphous CoFeB films grown on GaAs(001) substrates demonstrating significant in-plane uniaxial magnetic anisotropy were investigated by vector network analyzer ferromagnetic resonance. Distinct in-plane anisotropy of magnetic damping, with a largest maximum–minimum damping ratio of about 109%, was observed via analyzing the frequency dependence of linewidth in a linear manner. As the CoFeB film thickness

In this study, the low-temperature micro-photoluminescence (PL) technology was employed to investigate the transformation of nitrogen-vacancy (NV), silicon-vacancy (SiV) centers in diamond crystal. Results showed that the NV and SiV luminescence were controlled by electron irradiation followed by thermal annealing. Both centers vanished together with the emergence of neutral single vacancy (GR1 center)

The polarized ionic liquids (ILs) could generate intense electric fields on the surface of solid-state materials and create functional defects by ion migration within them, resulting in phase transitions of metal–insulator or paramagnet–ferromagnet, etc. Such a strong electric field even provides an opportunity for the control of spin ordering in antiferromagnetic (AFM) crystal which is difficult to

Raman spectroscopy has been established as one of the core experimental tools to study two-dimensional materials (2DMs) including graphene, black phosphorus, transitional metal chalcogenides, and other layered materials. If the polarization of the incident photons and the scattered photons are carefully controlled, the selection rules for the Raman scattering from phonon modes allow accurate mode assignments

We predict a high thermoelectric efficiency of HfTe5, based on the first-principles calculations of the electronic structure and thermal conductivity, and the transport coefficients obtained by using the semi-classical Boltzmann transport theory in a wide temperature and carrier concentration range. The lattice thermal conductivity is calculated based on the Slack model and the result is in good agreement

Iridate oxides display exotic physical properties that arise from the interplay between a large spin–orbit coupling and electron correlations. Here, we present a comprehensive study of the effects of hydrostatic pressure on the electronic transport properties of SrIrO 3 (SIO), a system that has recently attracted a lot of attention as potential correlated Dirac semimetal. Our investigations on untwinned

Using the Landau kinetic equation to study the non-equilibrium behavior of interacting Fermi systems is one of the crowning achievements of Landau’s Fermi liquid theory. While thorough study of transport modes has been done for standard three-dimensional Fermi liquids, an equally in-depth analysis for two dimensional Fermi liquids is lacking. In applying the Landau kinetic equation (LKE) to a two-dimensional

Recently, ultrastable glasses gained growing attention due to the revelation of the mechanism leading towards the understanding of glasses and glass transition in general. We report the adaptation of vapor deposition techniques to create ultrastable amorphous phases of Cu 50 Zr 50 with different mechanical properties. Investigations using atomic force acoustic microscopy reveal a connection between

The modern theory of orbital magnetization (OM) was developed by using Wannier function method, which has a formalism similar with the Berry phase. In this manuscript, we perform a numerical study on the fate of the OM under disorder, by using this method on the Haldane model in two dimensions, which can be tuned between a normal insulator or a Chern insulator at half filling. The effects of increasing

Multiferroic materials endowed with both dielectric and magnetic orders, are ideal candidates for a wide range of applications. In this work, we reported two phase transitions of MnI 2 at 3.45 K and 4 K by systemically measuring the magnetic-field and temperature-dependent magnetization of the MnI 2 thin flakes. Furthermore, we observed similar temperature and field-dependent behaviours for the magnetic

We report investigation of phonons and oxygen diffusion in Bi2O3 and (Bi0.7Y0.3)2O3. The phonon spectra have been measured in Bi2O3 at high temperatures up to 1083 K using inelastic neutron scattering. Ab initio calculations have been used to compute the individual contributions of the constituent atoms in Bi2O3 and (Bi0.7Y0.3)2O3 to the total phonon density of states. Our computed results indicate

Analysis of the resistivity, thermoelectric power, and heat capacity of Fe1-x Ni x Si is presented in this report. In-spite of Ni having two extra valence electrons as compared to Fe, the physical properties are observed to be dominated by holes. In this report, we have explained this unusual hole dominant scenario by a modified two narrow-band model. According to this model, the impurity electrons

We propose the model of a random polymer network, formed on the base on Erdös-Rényi random graph. In the language of mathematical graphs, the chemical bonds between monomers can be treated as vertices, and their chemical functionalities as degrees of these vertices. We consider graphs with fixed number of vertices N = 5 and variable parameter c (connectedness), defining the total number of links L

Sulfur vacancy in MoS2 has been found to have an important influence on the performance of optoelectronic devices. Here, we study the effect of sulfur vacancy and O2 adsorption on the electronic and optical properties in the two-dimensional ferroelectric CuInP2S6. It is revealed that a defect state appears at the top of valence band with the presence of sulfur vacancy. However, when O2 is chemisorbed

We report on the single crystal growth and transport properties of a topological semimetal CaAgBi which crystallizes in the hexagonal ABC-type structure with the non-centrosymmetric space group P63 mc (No. 186). The transverse magnetoresistance measurements with current in the basal plane of the hexagonal crystal structure reveal a value of about 30% for I∥[10̄0] direction and about 50% for I∥[1̅10]

Even if individual two-dimensional materials own various interesting and unexpected properties, the stacking of such layers leads to van der Waals solids which unite the characteristics of two dimensions with novel features originating from the interlayer interactions. In this topical review, we cover fabrication and characterization of van der Waals hetero-structures with a focus on hetero-bilayers

The iron(II) spin crossover complex Fe(1,10-phenanthroline)2(NCS)2, dubbed Fe-phen, has been studied with scanning tunneling microscopy, after adsorption on the 'herringbone' reconstructed surface of Au(111) for sub-monolayer coverages. The Fe-phen molecules attach, through their NCS-groups, to the Au atoms of the fcc domains of the reconstructed surface only, thereby lifting the herringbone reconstruction

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Two-dimensional (2D) materials have applications towards electronic devices, energy storages, and catalysis, et al. So far, most of elemental 2D materials are composed based on groups IIIA, IVA or VA. To expand the 2D material family, the orbital hybridization becomes a key factor to determine stability. Here we predict that sp2d3 hybridization of the outmost electrons in iodine and astatine can build

Thermodynamic stability and vibrational anharmonicity of single layer black phosphorene (SLBP) are studied using a spectral energy density (SED) method. At finite temperatures, SLBP sheet undergoes structural deformation due to the formation of thermally excited ripples. Thermal stability of deformed SLBP sheet is analyzed by computing finite temperature phonon dispersion, which shows that SLBP sheet

Employing high resolution hard x-ray photoemission spectroscopy, we investigate the electronic structure of an exotic Fe-based superconductor, CaFe2As2, which exhibits rich temperature pressure phase diagram and dichotomy on achieving superconductivity on application of pressure. The experimental valence band spectra exhibit significant differences for experiments at different surface sensitivities

Magnetic materials are typically described in terms of the Heisenberg model, which provides an accurate account of thermodynamic properties when combined with first principles calculations. This approach is usually based on an energy mapping between density functional theory and a classical Heisenberg model. However, for two-dimensional systems the eigenenergies of the Heisenberg model may differ significantly

Although the 1T' phase is rare in the transition metal dichalcogenides (TMDCs) family, it has attracted rapid growing research interest due to the coexistence of superconductivity, unsaturated magneto-resistance, topological phases etc. Among them, the quantum spin Hall (QSH) state in monolayer 1T'-TMDCs is especially interesting because of its unique van der Waals crystal structure, bringing advantages

A Heisenberg spin-s chain with alternating ferromagnetic (FM) ([Formula: see text]) and antiferromagnetic ([Formula: see text]) nearest-neighbor (NN) interactions, exhibits the dimer and spin-2s Haldane phases in the limits [Formula: see text] and [Formula: see text] respectively. These two phases are understood to be topologically equivalent. Induction of the frustration through the next NN FM interaction

Disorder components in surface anchoring orientation of a smectic-A liquid crystalline film (occurring, e.g., due to surface contamination sources) modify the thermal pseudo-Casimir interaction mediated between the bounding surfaces of the film. By considering a plane-parallel slab with bounding surfaces positioned normal to the layering field of the film, we study the anchoring disorder effects by

Controlling sub-microsecond desorption of water and other impurities from electrode surfaces at high heating rates is crucial for pulsed power applications. Despite the short time scales involved, quasi-equilibrium ideas based on transition state theory (TST) and Arrhenius temperature dependence have been widely applied to fit desorption activation free energies. In this work, we apply molecular dynamics

In this study, we demonstrate a self-excited oscillation induced in cholesteric liquid crystalline droplets under a temperature gradient. At equilibrium, a winding Maltese cross pattern with a point defect was observed via polarised microscopy in the droplets dispersed in an isotropic solvent. When the temperature gradient was applied, the pattern was deformed owing to the Marangoni convection induced

We present an experimental study of the high-pressure, high-temperature behaviour of cerium up to ∼22 GPa and 820 K using angle-dispersive x-ray diffraction and external resistive heating. Studies above 820 K were prevented by chemical reactions between the samples and the diamond anvils of the pressure cells. We unambiguously measure the stability region of the orthorhombic oC4 phase and find it reaches

A generalized spin-1 Blume-Capel model with distance/volume dependent nearest-neighbor exchange interaction is introduced and investigated using the standard methods of statistical mechanics. Besides of the volume-dependent magnetic energy, the static electromagnetic energy and anharmonic Einstein phonon contribution are also taken into account. Taking the simple volume dependence of all energy contributions

In this contribution, we report the results of theoretical calculation on the pressure induced phase transitions, structural, electronic and optical properties of the lithium based ternary LiBeX (X = As, Sb, Bi) compounds. These calculations are carried out using the full potential linearized augmented plane wave method. Our results show that these compounds undergo first order phase transitions. LiBeAs

Temperature modulated DSC is used to study the fragility of three different bulk metallic glass forming liquids. Through applying various modulation frequencies, the dynamic glass transition shifts in temperature, allowing to determine the temperature dependence of the average relaxation time for each system. The resulting fragilities are compared with fragility investigations in literature obtained

Superconductor-plasma based hyperbolic material (SPHM) and meta-material-plasma based hyperbolic materials (MPHM) are the plasma based composite hyperbolic materials. Using the effective medium theory, the permittivity of SPHM and MPHM has been investigated. Perpendicular and parallel permittivities, real and imaginary part, versus normalized frequency have been analyzed with variation of filling fraction

Considering a quantum network, here we propose two kinds of circular charge currents. These are referred as: net current in the full system and the current confined within a particular segment of the network. The network is composed of two rings, where one of the rings is subjected to a magnetic flux. Depending on the connectivity among the rings a new kind of states, insensitive to the magnetic flux

Kinetics of physical aging in archetypic 45S5 bioactive silicate glass composition with different types of phase separation are studied in situ below the glass transition temperature (T g). The qualitative nature of aging is found to be almost independent of the structural differences on the micrometer scale. A well-expressed step-like behavior in the enthalpy recovery kinetics is observed for aging

Layered ZrGeTe4 is a new type of ternary anisotropic semiconductor. The strong in-plane anisotropy may give us another degree of freedom for controlling electrical and optical properties, and designing advanced nanodevices. Using first-principles calculations, physical properties such as band structure, phonon vibration, and carrier mobility of layered ZrGeTe4 from bulk to monolayer were investigated

We investigate the localization in a one-dimensional modified Peierls model with a non-adiabatic dynamic method. Different from the polaron scenario, here the localization stems from extensive conserved local quantities in the disorder-free lattice. Both the entanglement entropy and out-of-time-ordered correlator (OTOC) show the oscillating feature of dynamically generated localization. Although the

Thin films with stable half-metallic (HM) character and 100% spin-polarization (SP) are required to be used in spintronic devices. The HM character has been predicted theoretically in many Heusler alloys thin films and confirmed by experiments. Full-Heusler alloy Ti2FeSn has been studied extensively. It has been reported that their (001)-oriented thin films with TiFe or TiSn terminations preserve 100%

The transition sequence in the Heusler alloy Ni50Mn34In8Ga8 has been determined from measurements of elasticity, heat flow and magnetism to be paramagnetic austenite → paramagnetic martensite → ferromagnetic martensite at ∼335 and ∼260 K, respectively, during cooling. The overall pattern of elastic stiffening/softening and acoustic loss is typical of a system with bilinear coupling between symmetry

We investigate the topological Weyl semimetal phases in a time reversal invariant spinless lattice model which has C 4v or C 2v point group symmetries. For the C 4v case, the model is characterized by eight Weyl points in the k z = π plane, while for the C 2v case, it is characterized by four Weyl points in the k z = π plane. For both cases, Fermi arcs can be realized on their surfaces. We find that

Light-activated colloidal assembly and swarming can act as model systems to explore non-equilibrium state of matter. In this context, creating new experimental platforms to facilitate and control two-dimensional assembly of colloidal crystals are of contemporary interest. In this paper, we present an experimental study of assembly of colloidal silica microparticles in the vicinity of a single-crystalline

Nanoscale rectifiers are known to have significant nanoelectronic and nanoheatronic applications. In the present work we theoretically analyze rectifying properties of a junction including a couple of quantum dots asymmetrically coupled to the electrodes. The charge and heat current rectification in the system is controlled by the dots occupation numbers and interdot Coulomb interactions. We examine

Spin-flip scattering from magnetic impurities has a strong pair-breaking effect in s-wave superconductors where increasing the concentration of impurities rapidly destroys superconductivity. For small Kondo temperature T K the destruction of superconductivity is preceded by the reentrant superconductivity at finite temperature range T c2 < T < T c1, while the normal phase reappears at T < T c2 ∼ T

The isothermal crystallization times and critical cooling rates of the liquid phase are determined for the two bulk metallic glass forming alloys Au49Ag5.5Pd2.3Cu26.9Si16.3 and Au51.6Ag5.8Pd2.4Cu20.2Ga6.7Si13.3 by using fast differential scanning calorimetry, covering the whole timescale of the crystallization event of the metallic melt. In the case of Au49Ag5.5Pd2.3Cu26.9Si16.3, a typical crystallization

We developed and implemented a numerical code called SAKE, which stands for (simulation code for atomistic Kohn-Sham equation). We developed it for first-principle electron transport calculations based on density-functional theory and non-equilibrium Green's function formalism. First, we present the central calculation parts of the formalism of the electronic states and transport properties for open

Motivated by practical implementation of transition-metal oxide-graphene heterostructures, we use all atom molecular dynamics simulations to study dynamics of water in a nano slit bounded by a transition metal oxide surface, namely, TiO2 termination of SrTiO3, and graphene. The resultant asymmetric, strong confinement produces square ice-like crystallites of water pinned at TiO2 surface and drives

This review aims at providing a retrospective, as well as a description of the state-of-the-art and future prospects regarding the theoretical and experimental characterisation of negative-U defects in semiconductors. This is done by complementing the account with a description of the work that resulted in some of the most detailed, and yet more complex defect models in semiconductors. The essential