M. Tanaka

Magnetic Weyl semimetals attract considerable interest not only for their topological quantum phenomena but also as an emerging materials class for realizing quantum anomalous Hall effect in the two-dimensional limit. A shandite compound Co₃Sn₂S₂ with layered kagome-lattices is one such material, where vigorous efforts have been devoted to synthesize the two-dimensional crystal. Here, we report a synthesis of Co₃Sn₂S₂ thin flakes

The intrinsic Hall effect allows for the generation of a nondissipative charge neutral current, such as a pure spin current generated via the spin Hall effect. Breaking of the spatial inversion or time reversal symmetries, or the spin-orbit interaction is generally considered necessary for the generation of such a charge neutral current. Here, we challenge this general concept and present generation and detection of a charge neutral current in a centrosymmetric material with little spin-orbit in

The quantum Hall system can be used to study many-body physics owing to its multiple internal electronic degrees of freedom and tunability. While quantum phase transitions have been studied intensively, research on the temperature-induced phase transitions of this system is limited. We measured the pure bulk conductivity of a quantum Hall antiferromagnetic state in bilayer graphene over a wide range of temperatures and revealed the two-step phase transition associated with the breaking of the lo

The author studies developments in epitaxial ferromagnetic heterostructures based on semiconductors towards spintronics and also presents a magnetotransport study on ferromagnetic III-V semiconductor heterostructures with high Curie temperature T/sub c/.

Unconventional magnetoresistance is a fascinating quantum phenomenon that continues to draw significant interest in condensed-matter physics. ${\mathrm{Mn}}_{3}{\mathrm{Si}}_{2}{\mathrm{Te}}_{6}$ has emerged as such a novel magnetoresistance (MR) material, notable for its largest MR exceeding conventional colossal magnetoresistance materials and pronounced directional anisotropy. Despite extensive research, the mechanisms driving MR in ${\mathrm{Mn}}_{3}{\mathrm{Si}}_{2}{\mathrm{Te}}_{6}$ remain

Summary form only given. This paper reviews the recent developments of epitaxial ferromagnetic heterostructures based on semiconductors for spintronics. The magnetotransport of prepared ferromagnetic III-V semiconductor heterostructures (Mn-delta-doped GaAs/Be-doped AlGaAs) and the control of ferromagnetism in the heterostructures by using gate electric field and light irradiation at relatively high Curie temperature (TC) (/spl sim/100 K) are also studied. This paper proposes and theoretically a

The quantum Hall system can be used to study many-body physics owing to its multiple internal electronic degrees of freedom and tunability. While quantum phase transitions have been studied intensively, research on the temperature-induced phase transitions of this system is limited. We measured the pure bulk conductivity of a quantum Hall antiferromagnetic state in bilayer graphene over a wide range of temperatures and revealed the two-step phase transition associated with the breaking of the lo

The physics of superconductivity in magic-angle twisted bilayer graphene (MATBG) is a topic of keen interest in moiré systems research, and it may provide insight into the pairing mechanism of other strongly correlated materials such as high-$T_{\mathrm{c}}$ superconductors. Here, we use DC-transport and microwave circuit quantum electrodynamics (cQED) to measure directly the superfluid stiffness of superconducting MATBG via its kinetic inductance. We find the superfluid stiffness to be much lar