We present a systematic method of creating type-III Dirac cones from degenerate directionally flat bands. Here, the directionally flat band means a completely dispersionless band only in a certain direction. The key strategy is to retain one of the directionally flat bands while making the other dispersive, by adding a perturbation having a selected form of a Hamiltonian matrix. Such a form of a perturbation

We investigate a superconducting state irradiated by a laser beam with spin and orbital angular momentum. It is shown that superconducting vortices are created by the laser beam due to heating effect and transfer of angular momentum of light. Possible experiments to verify our prediction are also discussed.

A whole series of expressions for four species of multipoles (electric, magnetic, magnetic toroidal, and electric toroidal) is provided as a complete basis set to describe arbitrary single-centered spinful electron systems. A compact formula to calculate matrix elements of these multipoles is also derived. A visualization method of an electronic state characterized in terms of multipoles is proposed

A method for analyzing the temperature and pressure dependence of the growth of an oxide film in the thermal oxidation of Si and SiC is devised. By using it, the experimental data of the oxide films thermally grown on Si(100) and Si(111) are analyzed to find that the barrier for the diffusion of O2 molecules in the transition region generated on Si(100) by thermal oxidation is larger than that on Si(111)

Using Bayesian spectroscopy, we have performed model selection to extract weak spectral components from an absorption spectrum of a Cu2O thin crystal sandwiched between a pair of MgO substrates. This absorption spectrum consisted of multiple absorption peaks due to the yellow excitonic series, as well as transitions of inter-bands and excitonic continuous states. Although the absorption intensity of

In this study, the higher-order tensor renormalization group (HOTRG) method is applied to a lattice glass model that has local constraints on the occupation number of neighboring particles represented by many-body interactions. This model exhibits first- and second-order transitions depending on a certain model parameter. The results obtained by using the HOTRG method for the model were confirmed to

A skyrmion crystal has internal degrees of freedom in terms of vorticity and helicity, which gives rise to fascinating types of skyrmion phases (Néel, Bloch, and anti-skyrmion). We show how the degeneracy lifting in tetragonal skyrmion crystals occurs in centrosymmetric itinerant magnets by focusing on microscopic interactions through the Fermi surface instability. We demonstrate that four types of

Pressure is a powerful tool for exploring novel phenomena in solid-state physics. We review the electronic states of single-crystalline EuT2X2 (T: transition metal, X: Si or Ge) and related compounds, together with the effect of pressure on these compounds. Eu ions in most of the Eu compounds are divalent (Eu2+), and the Eu2+ compounds order magnetically at low temperatures. The valence of the Eu ions

We experimentally investigate the control of atmospheric pressure discharge exhibiting chaotic oscillation. Atmospheric pressure discharge systems, before and during coalescence, are investigated based on photographs, time series, power spectra, and the largest Lyapunov exponents. Through these experiments, it is discovered that the merged discharge system after coalescence shows a periodic oscillation

We have studied 151Eu Mössbauer effects on EuRh2Si2 at a high pressure of 1.0 GPa as well as at ambient pressure. The compound shows a temperature-induced valence transition from the Eu2+ state to the nearly Eu3+ state with decreasing temperature at P ≥ 1.0 GPa. The synchrotron-radiation-based Mössbauer spectroscopy is applied to the measurements under a high pressure. The Eu2+ ratio abruptly decreases

The goal of this work is to calculate the fixation probability of a mutant on a fluctuating landscape, in particular, for the intermediate regime of parameters when selection and landscape fluctuations compete against each other. We derive the master equation for the fluctuating landscape, similar to the discrete version of a cross-diffusive process. Assuming an exponential ansatz for the fixation

We study the Kibble–Zurek mechanism in the transverse Ising chain coupled to a dissipative boson bath, using a new numerical method with the infinite time evolving block decimation combined with the discrete-time path integral. We first show the ground-state phase diagram and confirm that a quantum phase transition takes place in the presence of system-bath coupling. Then we present the time dependence

We show that when the electron and hole densities are unbalanced, observable nonlinear anomalous Hall effect and current-induced orbital magnetization appear at zero magnetic field in the weak charge ordering (CO) state of an organic two-dimensional Dirac fermion system, α-(BEDT-TTF)2I3. These current-induced phenomena are caused by a finite Berry curvature dipole resulting from inversion symmetry

We perform a microscopic study on the redistribution of electric charge near the surface of a model d-wave superconductor cut along the [110] direction, with a Fermi surface appropriate for cuprate superconductors, using the augmented quasiclassical equations. We identify two possible mechanisms for the redistribution of charged particles different from the well-known magnetic Hall effect, namely;

Dispersion-corrected density functional (DFT-D3) and Quantum perturbation theories are used to calculate the potential energy surface (PES), rotational states and energy rotational levels of adsorbed hydrogen molecule on Fe(OH)3. The PES is calculated as a function of vertical distance and polar and azimuthal angles. PES curves as a function of vertical distance, show that molecular hydrogen prefers

Particle-Gibbs (PG) method is a Markov chain Monte Carlo (MCMC) method for sampling from the joint posterior distribution of latent variables and parameters in a nonlinear state space model, which is a probabilistic time-series model. Recently, particle-Gibbs with ancestor sampling (PGAS) was proposed as a method with better sampling efficiency of PG. However, even with PG and PGAS, it is often difficult

We study the equilibrium states of a superconducting bilayer disk, which has been attracting attention as a base of a novel fractional flux quantum state. Our analysis is based on the Ginzburg–Landau theory, and we consider only the magnetic coupling between the layers. We show that various states, including the fractional flux quantum state, can be more easily realized by geometrical modifications

Quantum dynamics controlled by a time-dependent coupling constant are studied. It is proven that an energy eigenstate expectation value of work done by the system in a quench process cannot exceed the work in the corresponding quasi-static process, if and only if the energy eigenvalue is a concave function of the coupling constant. We propose this concavity of energy eigenvalues as a new universal

We report shifts of the threshold and wavenumber of ac-driven electroconvection (EC) in nematic liquid crystals under additionally applied deterministic and stochastic amplitudes and phases. A robust relationship (\(V_{\text{T}}/k_{\text{c}}^{2} = \textit{const.}\)) between the total effective voltage VT and wavenumber kc (at the onset of EC) was found, despite various shifts depending on the additional

Sparse modeling is generally applied to data analysis in the field of experimental physics, using statistical regularization methods such as the least absolute shrinkage and selection operator (LASSO). Therefore, it is essential to adjust the regularization parameter to minimize the estimation error. We focused on the cross validation error and analyzed the relation between the cross validation and

Reexamination of the 403 K phase transition of BaTiO3 by X-ray and calorimetric studies clarified that the formation and annihilation processes of monoclinic minor domains at the phase transition are important for the origin of the ferroelectric state. In previous studies, this occurred in two steps during cooling, and the crystals had a coherent hybrid structure with tetragonal major and monoclinic

We propose a new method to numerically calculate transition points that belongs to 2D Ising universality class for quantum spin models. Generally, near the multicritical point, in conventional methods, a finite size correction becomes very large. To suppress the effect of the multicritical point, we use a z-axis twisted boundary condition and a y-axis twisted boundary condition. We apply our method

Trilayer films consisting of ferromagnetic NiFe, nonmagnetic Cu or Ru, and antiferromagnetic FeMn layers were prepared by sputtering technique. The long-range exchange bias properties were investigated with magnetization curve measurements for the trilayer films with various nonmagnetic layer thicknesses tNM between 0 and 12 Å. Both the exchange bias and coercive fields were observed in the magnetic

We have measured and analyzed the nonlinear conduction of the Mott insulator Ca2RuO4 with square wave and square-pulse currents around room temperature with an infrared camera as a contactless thermometer. By combining the thermal diffusivity measurements, we have found that the temperature increase due to self heating is explained by the conduction of the Joule heat through the sample to the heat

The China Fusion Engineering Test Reactor (CFETR) is a nuclear fusion reactor that China is about to develop and manufacture independently. The central solenoid (CS) is one of its key components for inducing and maintaining the plasma during the tokamak operation. In phase II of CFETR, the maximum magnetic field of the CS magnet must be 17.5 T. In such a high magnetic field, NbTi and Nb3Sn cannot carry

Solid 4He shows unusual mechanical properties caused by interaction between dislocations and 3He impurities, both of which are highly mobile due to quantum nature of helium. Applying rotation to solid 4He changes its elasticity due to the change in motion of 3He impurities by centrifugal and Coriolis forces. We have examined the effect of steady rotation on the elastic properties of solid 4He using

Irradiating Cu2Mo(CN)8 ∙ 8H2O with blue light induces a global magnetization, whereas succeeding irradiations with red or longer-wavelength light demagnetize this material. We solve the time-dependent Schrödinger equation for an extended Hubbard model to reproduce the photoreversible magnetism. Monitoring the photoinduced optical-conductivity and angle-resolved-photoemission spectra, we reveal that

195Pt-NMR measurements of Pt nanoparticles with a mean diameter of 4.0 nm were performed in a high magnetic field of approximately μ0H = 23.3 T to investigate the low-temperature electronic state of the nanoparticles. The characteristic temperature T*, below which the nuclear spin–lattice relaxation rate 1/T1 deviates from the relaxation rate of the bulk, shows a magnetic-field dependence. This dependence

We show that a static electric field induces the transition from a ferromagnetic metal to an antiferromagnetic insulator owing to the Bloch oscillation of conduction electrons. In the steady state, the electric current is inversely proportional to the applied electric field, implying the nonperturbative insulating nature that is different from the Wannier–Stark localization. Possible experimental realization

For a classical discrete system under constant composition, the macroscopic structure in a thermodynamically equilibrium state can be typically determined through the so-called canonical average, including the sum over possible configurations on a configuration space. Although a set of configurations predominantly contributing to equilibrium properties should depend on temperature and many-body interactions

Various domain wall traps were designed, patterned and exploited by means of Lorentz microscopy and magnetic simulation. Those structures consist of two straight nanowires and connecting pads with different shapes. The connected pads linking those nanowires were varied in shapes and geometries. Domain walls can be created using continuous fields and those created walls are propagated under field pulses

The Potts model is a generalization of the Ising model with Q > 2 components. In the fully connected ferromagnetic Potts model, a first-order phase transition is induced by varying thermal fluctuations. Therefore, the computational time required to obtain the ground states by simulated annealing exponentially increases with the system size. This study analytically confirms that the transverse magnetic-field

We study vortex current distributions in narrow thin-film superconducting strips with the help of analytic expression of the vortex current derived within the London theory. Using definition of the vortex core “boundary” as a curve where the current reaches the depairing value, vortex core size and shape are estimated as a function of vortex position in the strip. We show that the core size near the

Analytic properties of the multiple spin density waves showing vortex structures, which have recently been found in the fcc Hubbard model using the generalized Hartree–Fock (GHF) approximation, have been investigated. It is shown that the 2Q multiple helical spin density waves (SDW) consist of two types of half-skyrmion vortices and two types of antivortices. In the 3Q multiple helical SDW, the half-skyrmion

Temperature dependence of the 115In-NMR spectra of CeRhIn5 is studied with the external magnetic fields 10° off the [100] and [001] axes. Our detailed analyses confirm that the AFM3 phase breaks the four-fold spin symmetry with the commensurate ordering vector of \(\boldsymbol{{Q}} = (0.5,0.5,0.25)\). Based on the observation of anistropic hyperfine fields, we also propose the symmetry lowering of

In this study, we illustrate the effect of Sb substitution on a single crystal of the layered superconductor LaO1−xFxBi1−ySbyS2 through specific heat measurements. LaO1−xFxBiS2 (x = 0.4 and 0.5) and LaO0.5F0.5Bi1−ySbyS2 (y = 0–0.20) were synthesized by the flux method under ambient pressure. The electronic specific heat Ce of LaO1−xFxBiS2 (x = 0.4 and 0.5) below ∼Tc can be explained by s-wave superconductivity

We report the temperature and pressure (\(p_{\textit{max}} \simeq 1.5\) GPa) evolution of the crystal structure of the Weyl semimetal Td-MoTe2 by combination of neutron diffraction and the X-ray total scattering experiments. We find that the fundamental non-centrosymmetric structure Td is fully suppressed and transforms into a centrosymmertic 1T′ structure at a critical pressure of pcr ∼ 1.2–1.4 GPa

We calculated the optical properties of an N-layer graphene by formulating the dynamical conductivity of each layer. This is the conductivity when an electromagnetic field is localized at a particular layer and differs from the standard conductivity calculated assuming a uniform field throughout all layers. By combining these conductivities with a transfer matrix method, we took into account the spatial

In order to enhance the critical current density (Jc) of superconductors, introduction of columnar defects (CDs) through swift-particle irradiation is effective. By dispersing the direction of CDs (splayed CDs), not only further enhancement of Jc has been confirmed but also an anomalous peak effect (APE) in Jc at a certain magnetic field determined by the irradiation dose was observed. It has been

We have investigated magnetic properties of the rare-earth based intermetallic compound Yb3Ni11Ge4.63 (YNG), where Yb3+ ions form a breathing-kagome lattice. Single-site 4f electron wavefunctions of the ground-state doublet are deduced from magnetization and heat capacity measurements. The Weiss temperatures are quite anisotropic as Θa = −0.01(2) K (H ∥ a) and Θc = −0.67(2) K (H ∥ c), indicating Ising-like

We succeeded in growing high-quality single crystals of ThCu2Si2 with the ThCr2Si2-type tetragonal structure by the Sn-flux method and measured the electrical resistivity, specific heat, and de Haas–van Alphen (dHvA) effect to study the Fermi surface properties. Comparing this experiment results with those of the full-potential LAPW band calculation, we found that the detected main dHvA branches named

The stationary Josephson current in a ballistic graphene system is theoretically studied with focus on a planar junction consisting of a monolayer graphene sheet on top of which a pair of superconducting electrodes is deposited. To characterize such a planar junction, we employ two parameters: the coupling strength between the graphene sheet and the superconducting electrodes, and a potential drop

A highly insulating bulk state and a tunable Dirac cone surface state are required for future spintronics device applications of spin-polarized surface states in three-dimensional topological insulators. Here, a slab model with heterostructural Bi2Se3-related quintuple layers is employed to conduct first-principles simulations. The computational results show that the Dirac-point energy can be optimally

We investigate the wave propagation characteristics and head-on collision of low-frequency magnetosonic waves in a dissipative plasma consisting of classical ions and degenerate inertia-less spin-up and spin-down electrons. Spin features are modeled via the macroscopic spin magnetization current and spin pressure. Employing the extended Poincare–Lighthill–Kuo perturbation method, a couple of Korteweg–de

To study the deviation from the Paschen curve under the micro-gap, the DC breakdown experiment with the electrode distance of 1–100 µm was carried out under atmospheric pressure in air. By deriving the approximate analytical formula of the ion number density near cathode, it is found that the higher ion number density near cathode will produce an additional electric field with the increase of applied

The deformation of director field in a nematic liquid crystalline droplet under an electric field was analyzed. In the absence of the electric field, a Maltese cross pattern was observed at the center of the droplet. Applying the electric field to the droplet, we observed that the cross pattern deformed owing to the dielectric anisotropy of the liquid crystal. In addition, under a direct-current (DC)

A mesoscopic circuit, where field quantization (e.g., coherent states and squeezed states) can be exhibited, is one of the ideal quantum systems for manifesting diverse quantum field theoretical phenomena and thermally statistical characteristics. Because of inevitable electromagnetic coupling (e.g., mutual capacitor coupling and mutual inductor coupling) in two neighboring mesoscopic electric circuits

In this paper the role of the dust particles in weakening or scaling down the blast wave produced by an atmospheric nuclear explosion is investigated. A mathematical model has been considered to study the one-dimensional unsteady flow of an inviscid, non-ideal gas with dust particles. The effects of the dust particles and the non-ideal parameter on the blast wave radius and the peak pressure for an

We propose a modified quantum annealing protocol, i.e., pulsed quantum annealing (PQA), in order to increase the success probability by a pulse application during the quantum annealing process. It is well known that the success probability of the conventional quantum annealing is reduced due to the Landau–Zener transitions. By applying a pulse to the system, we modulate the success probability and

Recently, the use of neural quantum states for describing the ground state of many- and few-body problems has been gaining popularity because of their high expressivity and ability to handle intractably large Hilbert spaces. In particular, methods based on variational Monte Carlo have proven to be successful in describing the physics of bosonic systems such as the Bose–Hubbard (BH) model. However,

The spontaneous motion of a camphor particle with a slight modification from a circle is investigated. The effect of the shape on the motion is examined by the perturbation method. We introduce a slight n-mode modification from a circle, where the profile is described by \(r = R(1 + \epsilon \cos n\theta )\) in polar coordinates. The results predict that a camphor particle with an n = 3 mode modification

We present first-principles phonon calculations for ferromagnetic and paramagnetic (disordered local moment) states in B2-type (FeCo, MnNi) and L10-type (CoPt, FePt, FePd) materials. The calculations show a clear relationship between the degree of the phonon softening due to magnetic disordering and crystal symmetry. We discuss the mechanism of the phonon softening by introducing a concept, exchange

We examine quasi-two-dimensional superconductors near half-filling under uniaxial pressures perpendicular to conductive layers (hereafter called perpendicular pressures). It is a natural conjecture that the perpendicular pressure decreases the transition temperature Tc because it increases the interlayer electron hopping energy tz, which weakens the logarithmic enhancement in the density of states

The magnetic-field-induced A-phase for H ∥ [111] in cubic chiral antiferromagnet EuPtSi has been recently identified as a skyrmion lattice phase. We examined precise magnetic-field angle dependences of the magnetic-field-induced phases via magnetoresistance measurement using a high-quality single crystal sample. When the magnetic field is tilted from the [001] to [100] direction, two magnetic-field-induced

Motivated by the metal–insulator transition in layered organic compound λ-(BETS)2FeCl4, where naive theoretical calculations predict metallic phase after the antiferromagnetic transition, we propose a spin-density wave assisted Mott transition mechanism. We consider a two-band system consisting of a band with good Fermi surface nesting and the other with poor nesting. Neither the spin-density wave

Emission intensity \(\epsilon \) from plasmas is a complicated function of electron temperature Te and electron density ne. To understand the dependence of \(\epsilon \) on Te and ne, an experimental comparison between tomography data (local \(\epsilon \) of ArII) and Langmuir probe data (Te and ne) in a linear plasma device PANTA is presented in this paper. In the comparison, the local emission intensity

Magnetic properties of an Yb-based semiconductor YbCuS2 with a zigzag chain of Yb3+ ions were studied. The Curie–Weiss behavior of the magnetic susceptibility χ(T) indicates antiferromagnetic interaction and an isolated Kramers doublet ground state with effective spin-1/2. Magnetic specific heat Cm/T exhibits a sharp peak at TO = 0.95 K, where the magnetic entropy is 20% of R ln 2, indicating strong