JournalJPSJ

Thermoelectric Response in Strongly Disordered Systems

Based on the Kubo–Luttinger linear response theory, we discovered that the low-T Seebeck coefficient for Mott variable-range hopping in a d-dimensional system varies as S ∝ T^d/(d+1), which is different from the conventional S ∝ T^{(d−1)/(d+1)}. In addition, the experimental data for S of CuCrTiS₄ at low T are in excellent agreement with our prediction S ∝ T^3/4 (d = 3).

Electronic transport in condensed matter

Birefringence Imaging-Based Investigation of Stress-Induced Phase Transitions in SrTiO₃

The spatial distributions of ferroelectric and structural phase transitions in quantum paraelectric SrTiO₃ under uniaxial stress were microscopically observed using birefringence imaging techniques.

Dielectric, optical, and other properties in condensed matter

Topology-Based Method for Determining the Order Parameter of the Putative Spin-Triplet Superconductor UTe₂

The intrinsic anomalous thermal Hall effect can be an effective probe for the order parameters of non-unitary pairing states of the putative spin-triplet superconductor UTe₂

Superconductivity

Inertial Focusing of Red Blood Cells in Square Tube Flows

Red blood cells flowing through square capillary tubes were observed to migrate towards four points located on the diagonal in the tube cross-section, owing to their deformability and inertia.

Electromagnetism, optics, acoustics, heat transfer, and classical and fluid mechanics

Can a Node-Less Wave Function Have Higher Energy than Node-Full Ones?

“The energy level of an electron state increases as the number of nodes in its wave function increases.” The preceding statement, often found in textbooks, was challenged by our large-scale DFT (density-functional theory) calculations performed for the decavacancy in Si crystal.

Electron states in condensed matter

Structure and mechanical and thermal properties in condensed matter

Optical Tweezer Arrays with Ytterbium Atoms for Studying Quantum Phenomena

A neutral Rydberg atom tweezer array is a promising platform for quantum computation. In this study, featuring its metastable excited state, an array of single ytterbium atoms trapped in micro-optical tweezers was constructed. This overcomes many problems in conventional systems using alkali atoms.

Atomic and molecular physics

Spin-Orbit Coupled Electrons on Kagome Lattice Give Rise to Various Magnetic Orderings

Diverse magnetic orderings are found to be produced by spin-orbit coupled electrons on the kagome lattice. This finding provides a unified guiding principle for the design of magnetic topological materials.

Electronic structure and electrical properties of surfaces and nanostructures

A New Route to the Realization of Topological Superconductivity

We theoretically suggest that topological Weyl superconductivity can be realized by applying a supercurrent to noncentrosymmetric line-nodal superconductors with spin–orbit coupling.

Superconductivity

Electronic structure and electrical properties of surfaces and nanostructures

Exploring Superconductivity in the Close Proximity of Polar-Nonpolar Structural Phase Transition

A polar-nonpolar structural phase transition and corresponding increase in superconducting transition temperature T_c are observed in chemically doped PtBi₂. T_c increases as the system approaches the phase boundary.

Superconductivity

Giant Vortices of Fish: Mechanisms and Patterns

The origin of giant rotating clusters of fish is revealed by a new agent-based model that incorporates the topological nature of interactions and the escape response characteristic to fish.

Cross-disciplinary physics and related areas of science and technology

Origin of Metamagnetic Transition (MMT) in the Spin-Triplet Superconductivity in UTe₂

State-of-the-art magnetostriction measurements in a pulsed-magnetic field reveal the origin of a metamagnetic transition of spin-triplet superconductor UTe₂. We propose that the uranium valence fluctuation plays a crucial role in its metamagnetic and superconducting transitions.

Superconductivity

Magnetic properties in condensed matter

Unraveling the Unique Properties of Icosahedral Quasicrystals

Scientists review the magnetism, non-Fermi liquid behavior, and quantum critical behavior observed in icosahedral quasicrystals (QCs), and compare these properties with that of heavy fermions and approximant crystals.

Magnetic properties in condensed matter

Structure and mechanical and thermal properties in condensed matter

Cross-disciplinary physics and related areas of science and technology

New Chiral Molecular Ferroelectrics

A new chiral ferroelectric material is discovered in a purely organic system, 1,1’-bi-2-naphthol・2 dimethyl sulfoxide (BINOL・2DMSO).

Dielectric, optical, and other properties in condensed matter

Tensor Networks Across Physics

Researchers from Japan provide the first comprehensive review of the historical development of tensor networks from a statistical mechanics viewpoint, with a focus on its theoretical background.

Mathematical methods, classical and quantum physics, relativity, gravitation, numerical simulation, computational modeling

Statistical physics and thermodynamics

Magnetic properties in condensed matter

Towards Radionuclide Cancer Therapy with High Purity ¹⁷⁷Lu from Enriched ¹⁷⁶Yb Samples

A method was developed to estimate the isotopic compositions of enriched ¹⁷⁶Yb sample required for producing radionuclide ¹⁷⁷Lu used for cancer therapy, with high radionuclide purity in accelerators.

Nuclear physics

Cross-disciplinary physics and related areas of science and technology

Understanding Relaxor Ferroelectrics with Simple Landau Theory

Third-order nonlinear dielectric susceptibility is measured in the paraelectric phase of Pb(Sc_1/2Ta_1/2)O₃. The linear and nonlinear dielectric susceptibility results can be consistently explained based on the Landau-type free-energy density.

Dielectric, optical, and other properties in condensed matter

Structure and mechanical and thermal properties in condensed matter

Cross-disciplinary physics and related areas of science and technology

Spin Transport in a Two-Dimensional Tilted Dirac Electron System

We propose that spin current in an organic conductor, α-(BETS)₂I₃, is an appropriate physical quantity to detect the topological nature of the material whose electrons obey a quasi-two-dimensional Dirac equation.

Electronic transport in condensed matter

Electronic structure and electrical properties of surfaces and nanostructures

Violation of Fluctuation-Dissipation Theorem Results in Robustness of Fluctuation Against Localization

We study equilibrium current fluctuations in systems without time-reversal symmetry, violating the fluctuation-dissipation theorem. Notably, the off-diagonal fluctuation is insensitive to system imperfections in contrast to other fluctuations and conductivity.

Statistical physics and thermodynamics

Electronic transport in condensed matter

Electronic structure and electrical properties of surfaces and nanostructures

Four-Dimensional XY Quantum Phase Transition in Superfluid Helium-4

Liquid helium confined in nanopores exhibits a quantum superfluid transition at absolute zero. Investigations have revealed that the quantum nature also dominates the finite-temperature superfluid transition, obeying a simple mean-field theory.

Structure and mechanical and thermal properties in condensed matter

Topological Aspects of a Nonlinear System: The Dimerized Toda Lattice

A nonlinear topological phase is shown to emerge in the dimerized Toda lattice. It is experimentally detectable by measuring the voltage propagation in electric circuits.

Electronic structure and electrical properties of surfaces and nanostructures

Electronic transport in condensed matter

Unusual Nonlinear Conductivity in Charge-Ordered α-(BEDT-TTF)₂I₃

Unusual nonlinear conduction is detected in organic molecular salt α-(BEDT-TTF)₂I₃. The observed third-order nonlinear conductivity implies a quadrupole instability hidden in this charge-ordered organic salt.

Electronic transport in condensed matter

Economic Irreversibility: The Universal Guiding Principle of Infection Control

It is preferable to avoid lockdowns, as lockdowns at seriously spread phases are very expensive. It would be economically better to utilize less intense countermeasures as early as possible to avoid lockdowns in later phases.

Statistical physics and thermodynamics

Cross-disciplinary physics and related areas of science and technology

Realizing Spin Liquids Experimentally with Kapellasite-type Quantum Kagome Antiferromagnet

This study reports the observation of the spin fluctuation in a quantum kagome antiferromagnet CaCu₃(OH)₆Cl₂·0.6H₂O which persists down to 82 mK using the μSR technique.

Magnetic properties in condensed matter

Phosphorous-Based Zintl Compounds as Viable Semimetals

A black-phosphorus-derived Zintl compound, MoP₄, is obtained by high-pressure synthesis. The material exhibits a non-quadratic large magnetoresistance and semi-metallic Seebeck behavior, as predicted by the first principles calculations yielding massive and non-symmorphic Dirac semimetal states.

Electronic structure and electrical properties of surfaces and nanostructures

Structure and mechanical and thermal properties in condensed matter

Electron states in condensed matter

New Systematic Analysis Method of Identifying Microscopic Essential Couplings

We propose a systematic method of identifying essential model parameters for nonlinear response tensors. The analysis results reveal fundamental couplings in nontrivial responses and promote further development of multiferroic responses.

Electronic transport in condensed matter

Dielectric, optical, and other properties in condensed matter

Cross-disciplinary physics and related areas of science and technology

Shedding Light on Nonreciprocal Directional Dichroism at High Magnetic Fields in a Multiferroic Material

Large optical nonreciprocal directional dichroism, coupled with an antiferromagnetic order parameter, is observed in a high magnetic field via magneto-optical spectroscopy combined with a pulse magnet technique.

Dielectric, optical, and other properties in condensed matter

Magnetic properties in condensed matter

Twist in the Tale: Exploring the Dielectric Screening Effect in Twisted Bilayer Graphene

Although the screening of an external electric field, strongly influences the electronic states of two-dimensional material stack, it is not well understood. Magnetotransport measurements of twisted double bilayer graphene uncovered the screening of atomic layers.

Electronic structure and electrical properties of surfaces and nanostructures

Electronic transport in condensed matter

A Two-step Creation of Phonon Entanglement with Quantized Light

Dynamics of photoinduced quantum entanglement generation between phonons is theoretically revealed. The results contribute to the study of fundamental theoretical problems within quantum dynamics of photoinduced phase transitions and quantum information science.

Dielectric, optical, and other properties in condensed matter

Electromagnetism, optics, acoustics, heat transfer, and classical and fluid mechanics

Mathematical methods, classical and quantum physics, relativity, gravitation, numerical simulation, computational modeling

Spin-Wave Dynamics in Antiferromagnets under Electric Current

Electric current causes a Doppler effect in spin waves in ferromagnets through a spin-transfer torque. We report that antiferromagnets allow two such spin-transfer torques and present a microscopic analysis that interpolates ferro- and antiferromagnetic transport regimes.

Electronic transport in condensed matter

Magnetic properties in condensed matter

Exploring the Basic Principles and Functionalities of Spintronic Thermal Management

Scientists propose a new spin caloritronics concept called “spintronic thermal management” and provide a comprehensive overview of basic principles, physical behaviors, and heat control functionalities associated with the concept.

Magnetic properties in condensed matter

Structure and mechanical and thermal properties in condensed matter

How Good is the Transition-State Theory?

For the first time, the main assumption of the transition-state theory for the decay of complex quantum systems across a potential barrier was realized using a microscopic many-body Hamiltonian.

Statistical physics and thermodynamics

Nuclear physics

The Mysteries of Charge Order and Charge Fluctuations in Cuprate Superconductors

This Special Topics issue condenses the latest research on the enigmatic characteristics of high-temperature superconductivity in cuprates through the observation and elucidation of charge order, charge fluctuations, and other phenomena.

Superconductivity

Dielectric, optical, and other properties in condensed matter

Structure and mechanical and thermal properties in condensed matter

Magnetic properties in condensed matter

Analyzing Photoinduced Phase Transitions in an Organic Salt Using Floquet Theory

Rich nonequilibrium phase diagrams, including photoinduced topological insulator phases, were theoretically predicted for an organic salt α-(BEDT-TTF)₂I₃ when irradiated by elliptically polarized light.

Electronic structure and electrical properties of surfaces and nanostructures

Dielectric, optical, and other properties in condensed matter

Materials with Dirac Loops: A Potential Solution for Next-generation Electronics

A high-quality single crystal of rhenium oxide shows significantly large magnetoresistance, potentially originating from a unique electronic structure called “hourglass Dirac chain” protected by the symmetry of the crystal.

Electronic transport in condensed matter

Electron states in condensed matter

Electronic Structure Transformation in a Magnetized Topological Semimetal

We theoretically show that the nodal structures in topological semimetals, including Weyl points and nodal lines, can be switched by magnetic orders, accompanied by localized states at magnetic domain walls.

Electronic structure and electrical properties of surfaces and nanostructures

Measurements and Implications of Shot Noise in Mesoscopic Systems

Shot noise measurements provide rewarding insights into system properties, non-equilibrium phenomena, and quantum effects in mesoscopic systems.

Electronic transport in condensed matter

Magnetic properties in condensed matter

Superconductivity

Exploring the Thermoelectric Properties of Nitrogen-doped Carbon Nanotubes

A semiconducting carbon nanotube doped with an optimal concentration of nitrogen delivered a thermoelectric power substantially higher than that delivered by commercial Bi₂Te₃ alloys.

Electronic transport in condensed matter

Structure and mechanical and thermal properties in condensed matter

Cross-disciplinary physics and related areas of science and technology

Finding Pattern in Randomness: Brownian Motion of Skyrmions

The chiral properties of the Brownian motion of magnetic skyrmions in one- and two-dimensional systems in thermal equilibrium are reported.

Structure and mechanical and thermal properties in condensed matter

Electronic transport in condensed matter

Magnetic properties in condensed matter

Nonlinear Thermoelectric Transport Will Open a New and Exotic Way to Detect Topological Nature of Dirac Electrons in Solids

Recently, it was proposed that a novel nonlinear anomalous Ettingshausen effect enabled a new and exotic approach to observe topological nature of Dirac electrons in solids using thermoelectric properties.

Electronic transport in condensed matter

Electronic structure and electrical properties of surfaces and nanostructures

Structure and mechanical and thermal properties in condensed matter

Semiconductor to Semimetal to Superconductor: An Excitonic Journey

A phase diagram was constructed for Ta₂NiSe₅, a promising candidate for excitonic insulators, using high pressure as a tuning parameter. The results indicated pressure-induced superconductivity in the semimetallic phase.

Superconductivity

Electronic transport in condensed matter

Exploring the Physics of Ferrimagnets for Future Spintronics Applications

This Special Topics collection of the Journal of the Physical Society of Japan covers recent progress in spintronics research on ferrimagnetic materials.

Structure and mechanical and thermal properties in condensed matter

Electronic transport in condensed matter

Magnetic properties in condensed matter

Cross-disciplinary physics and related areas of science and technology

Understanding Skyrmion Crystal Formation in EuPtSi

We theoretically demonstrate that the interplay between the spin-charge and spin-orbit couplings in itinerant magnets stabilizes field-direction sensitive, short-period skyrmions. Our results can aid in engineering short-period skyrmions.

Magnetic properties in condensed matter

Will Magnetic Properties near Pressure Induced Quantum Critical Phenomena Be Elucidated?

Hiraoka et al. developed an opposed anvil-type pressure cell for magnetization measurements which combines a large sample space and is capable of generating higher pressures up to 6.3 GPa.

Measurement, instrumentation, and techniques

Magnetic properties in condensed matter

Uncovering the Superlattice Structure of Calcium Iridium Oxide at Phase Transition

Order parameter of non-magnetic phase transition at 105 K, which is called "hidden order", was revealed in spin-orbit coupled iridate Ca₅Ir₃O₁₂. This discover of order parameter with rotational and directional degrees of freedom in atomic scale will lead to development of energy saving devices with a fast cross-correlated response.

Electron states in condensed matter

Structure and mechanical and thermal properties in condensed matter

Overlooked Materials Host Rich Physics of Strongly Correlated Electrons

An international team of researchers reviews the research progress on strongly spin-orbit coupled systems, providing an overview of theoretically predicted electronic phases, candidate materials, and unusual experimental observations.

Electron states in condensed matter

Magnetic properties in condensed matter

Electronic transport in condensed matter

Detecting Weak Quantum Magnetism at High Pressures

Improved device and method to measure magnetization under high pressure was developed, which brings a quick tool to screen phases of interest in weakly magnetic materials including quantum magnets.

Measurement, instrumentation, and techniques

Magnetic properties in condensed matter

Exotic Superconducting States in Transition Metal Tellurides

Nb₂Pd₃Te₅ was found to show bulk superconductivity at 3.3 K. In contrast, Ta₂Pd₃Te₅, a 5d analogue of Nb₂Pd₃Te₅, showed nonmetallic electronic conduction, which was changed to show bulk superconductivity by chemical doping.

Superconductivity

Descriptor of Thermogalvanic Cell for Waste-heat Harvesting

The scaling relation between the Seebeck coefficient and solvent viscosity would enable for the design of improved thermogalvanic cells.

Structure and mechanical and thermal properties in condensed matter

How a Potentially Novel Effect Converts AC Current into DC Heat Flow

A novel current-induced thermoelectric phenomenon, the nonlinear anomalous Ettingshausen effect, was discussed. As an example, the weak charge ordering state in an organic conductor α-(BEDT-TTF)₂I₃ was focused on. This effect generates a transverse heat current with rectifying characteristics, namely unidirectionality even under AC fields.

Electronic transport in condensed matter

Electronic structure and electrical properties of surfaces and nanostructures

Structure and mechanical and thermal properties in condensed matter

Electric Quadrupole Orders in f-Electron Systems on the fcc Lattice

We theoretically showed that electric quadrupoles in some heavy fermion materials exhibit a very rich phase diagram including unique partially-ordered phases stabilized by an interaction specific to these systems.

Magnetic properties in condensed matter

Dielectric, optical, and other properties in condensed matter

Statistical physics and thermodynamics