The University of Tokyo · 물리·천문학
나가사 교수의 연구실은 강한 전자 상호작용과 스핀-오비트 결합이 양자물질의 비보존적 및 위상적 성질을 이끄는 메커니즘을 연구합니다. 주요 연구 분야로는 비보존 대칭성에 기인한 전기적·자기적 비선형 현상, 초전도체에서의 비정상 상태 성질, 그리고 위상적 전류의 기원을 밝히는 베리 위상 이론이 포함됩니다. 특히, 이론과 실험의 융합을 통해 비보통 초전도체와 고체에서의 이상한 홀 효과, 자기치랄 이성향성 등 새로운 물리 현상을 규명하고자 합니다.
표시된 성과는 수집된 데이터 기준으로 산출되며, 일부 차이가 있을 수 있습니다.
The anomalous Hall effect (AHE) occurs in solids with broken time-reversal symmetry, typically in a ferromagnetic phase, as a consequence of spin-orbit coupling. Experimental and theoretical studies of the AHE are reviewed, focusing on recent developments that have provided a more complete framework for understanding this subtle phenomenon and have, in many instances, replaced controversy by clarity. Synergy between experimental and theoretical works, both playing a crucial role, has been at the
We study a version of the uniform resonating-valence-band state in which fermions and spinless bosons are coupled by a gauge field. We show that above the Bose-Einstein temperature, the boson inverse lifetime due to scattering by the gauge field is of order kT, which suppresses the condensation temperature and leads to a linear T resistivity. The Hall number is proportional to the hole density and temperature dependent. The single-particle spectral weight exhibits a continuum plus a broadened pe
Lack of spatial inversion symmetry in crystals offers a rich variety of physical phenomena, such as ferroelectricity and nonlinear optical effects (for example, second harmonic generation). One such phenomenon is magnetochiral anisotropy, where the electrical resistance depends on the current direction under the external magnetic field. We demonstrate both experimentally and theoretically that this magnetochiral anisotropy is markedly enhanced by orders of magnitude once the materials enter into
