Naoki Ogawa

Record-high Glass coefficient in the shift current response of a ferroelectric halide perovskite

Koma Miki, Masao Nakamura, Asahi Yamada, Gurvan Bosser et autres

Ferroelectric halide perovskites provide a fertile platform for optoelectronic functions based on the bulk photovoltaic effect, where broken inversion symmetry couples with quantum geometry of wave functions. The most prominent manifestation is the shift current, second-order nonlinear photocurrent arising from change in …

jp (code pays fourni par la source)

Layer photovoltaic effect in a two-dimensional antiferromagnet with parity–time symmetry

Yu Dong, Sota Kitamura, Yuki M. Itahashi, Daniel G. Chica et autres

jp, us (code pays fourni par la source)

All-optical control of antiferromagnetic domains via an inverse optical magnetoelectric effect

S. Toyoda, Vilmos Kocsis, Y. Tokunaga, I. Kézsmárki et autres

jp, de (code pays fourni par la source)

Large terahertz photovoltaic effect enhanced by phonon excitations in ferroelectric semiconductor SbSI

Yoshihiro Okamura, Guang-Yu Guo, Y. Kaneko, Masao Nakamura et autres

Quantum geometry of Bloch electron in crystalline solids produces various exotic quantum phenomena. The shift current photovoltaic effect driven by the photo creation of quasiparticle is one such emerging example that enables the conversion from terahertz photon into dc charge current with …

jp, tw (code pays fourni par la source)

Harmonic and subharmonic magnon generation in a surface-acoustic-wave resonator

Yunyoung Hwang, Liyang Liao, Jorge Puebla, Marco Brühlmann et autres

jp, at (code pays fourni par la source)

Quantum geometry in low-energy linear and nonlinear optical responses of the magnetic Rashba semiconductor (Ge,Mn)Te

Tsubasa Takagi, Hikaru Watanabe, Ryutaro Yoshimi, Yuki Sato et autres

Quantum geometry appears as a key factor in understanding the optical properties of quantum materials, with the anticipation on diverging or quantized responses near the Dirac and Weyl points. Here we investigate linear and nonlinear optical responses -- optical conductivity and injection …

jp (code pays fourni par la source)

Influences of Chip Shape on Scaling in Chip-on-Wafer Hybrid Bonding

Koki Onishi, Sotetsu Saito, T. Osako, Takaaki Hirano et autres

This study investigated the influences of chip warpage and thickness on scaling in chip-on-wafer hybrid bonding. Scaling, a key bonding misalignment parameter, depends on the bonding process and substrate properties. Effective control of scaling is crucial for interconnecting Cu pads with finer …

jp (code pays fourni par la source)

Emergence of Ferroelectric Topological Insulator as Verified by Quantum Hall Effect of Surface States in (Sn,Pb,In)Te Films

Ryutaro Yoshimi, Ryosuke Kurihara, Yoshihiro Okamura, Naoki Ogawa et autres

Emergent phenomena arising from nontrivial band structures based on topology and symmetry have been attracting keen interest in contemporary condensed-matter physics. Materials such as SnTe and PbTe are one such example, which demonstrate a topological phase transition while showing ferroelectric instability derived …

jp (code pays fourni par la source)

Pressure-induced quantum melting of chiral spin order and subsequent transition to a degenerate semiconductor state in FeGe

Yukako Fujishiro, C. Terakura, Atsushi Miyake, Naoya Kanazawa et autres

The authors reveal here anomalous charge transport upon melting of chiral spin orders, such as helical and skyrmion spin textures, in the itinerant chiral magnet FeGe. Under high pressure, significant modifications in the electronic structure induce a metal-to-semiconductor transition. Remarkably, a spontaneous …

jp, hu (code pays fourni par la source)

Emergence of ferroelectric topological insulator as verified by quantum Hall effect of surface states in (Sn,Pb,In)Te films

Ryutaro Yoshimi, Ryosuke Kurihara, Yoshihiro Okamura, Naoki Ogawa et autres

Emergent phenomena arising from nontrivial band structures based on topology and symmetry have been attracting keen interest in contemporary condensed-matter physics. Materials such as SnTe and PbTe are one such example, which demonstrate a topological phase transition while showing ferroelectric instability derived …

Strongly enhanced shift current at exciton resonances in a noncentrosymmetric wide-gap semiconductor

Masao Nakamura, Yang‐Hao Chan, Takahiro Yasunami, Y.S. Huang et autres

Excitons are fundamental quasiparticles that are ubiquitous in photoexcited semiconductors and insulators. Despite causing a sharp and strong photoabsorption near the interband absorption edge, charge-neutral excitons do not yield photocurrent in conventional photovoltaic processes unless dissociated into free charge carriers. Here, we …

jp, tw (code pays fourni par la source)

Chronic Illness and visiting clinic before hospitalization at the onset of Stroke: Shiga Registry

Melody Kiyohara, Naomi Miyamatsu, Tomohiro Harada, Naoyuki Takashima et autres

Abstract Background Prompt action at stroke onset is required to improve prognosis. Some previous studies indicated that visiting local clinics may initially delay access to specialized care. We examined the relationship between the presence of chronic diseases known as risk factors for …

jp (code pays fourni par la source)