JPS Hot Topics

Ferromagnetism is the spontaneous alignment of magnetic moments in the same direction, even in the absence of an external magnetic field. This alignment results in a finite spontaneous magnetization within each magnetic domain. When a ferromagnet is cooled from the paramagnetic state in an external magnetic field, the field selects the preferred direction of magnetization, […]

The development of functional materials by thermal management is expected to be a crucial technology for solving modern societal problems, such as the efficient use of energy. Recently, chiral materials, in which atoms are arranged in a helical pattern, have been studied as new functional materials because they exhibit unique lattice vibrations with circular motion […]

Viscosity is generally understood as resistance to flow. When a liquid is sheared, it produces a stress that opposes the imposed motion, and mechanical energy is dissipated as heat. However, in systems that are continuously driven by an external energy source, part of the supplied energy can be converted into organized mechanical motion. Such a […]

Research into ferromagnetic and antiferromagnetic systems remains a hot topic in condensed-matter physics. Diffraction-based characterization is suitable for determining the average magnetic structure and successfully explaining various macroscopic properties. However, these methods are insufficient for elucidating the local structures of minor elements, such as dopants, prompting the development of more effective characterization techniques. Atomic-resolution holography […]

Primordial black holes (PBHs) are potential candidates for dark matter and offer a unique way to probe the inflationary models that describe the very early universe. They are hypothesized to have formed from the gravitational collapse of regions with extremely high density in the moments after the Big Bang. As a result, the predicted number […]

The concept of symmetry in quantum field theory has expanded substantially in recent years. Traditionally, symmetry was understood as a set of invertible transformations with the structure of a group. Recently, however, symmetry has been viewed more generally in terms of topological defects in a theory. From this perspective, the composition of symmetry transformations is […]

In energy devices, such as batteries and liquid thermoelectric converters, electron transfer occurs between ions dissolved in the electrolyte and the electrodes. For current to continue flowing in such devices, new ions must be supplied continuously to the electrode surface from the bulk region of the electrolyte. This is because ions that have undergone electron […]

Angle-resolved hard X-ray photoelectron spectroscopy (AR-HAXPES) can probe buried chemical states nondestructively. Hard X-rays yield photoelectrons with long inelastic mean free paths. Hence, by measuring the spectra at multiple take-off angles, the depth sensitivity changes and thin-film thickness can be inferred for laminated materials. However, least-squares peak fitting is sensitive to initial values and analyst […]

Recent advances in experimental techniques used for probing and controlling nanofabricated devices have stimulated a strong interest in theoretically studying their nonequilibrium properties. In thermal equilibrium, electrons follow the Fermi–Dirac distribution, whereas under nonequilibrium conditions, the electron distribution generally deviates from the Fermi–Dirac form. A typical example of this is a nanowire connected to two […]

Superconductivity is a remarkable quantum phenomenon in which electrons form paired bound states, known as Cooper pairs, leading to zero electrical resistance. Bardeen–Cooper–Schrieffer (BCS) theory has long provided the microscopic foundation for conventional superconductivity, describing Cooper pairs with antiparallel electron spins: spin‑singlet pairing. This theory explains a wide range of superconducting materials. By contrast, electrons […]