Theory of spin torques emerging from band topology

バンドトポロジーに起因したスピントルクの理論

荒木 康史   

Araki, Yasufumi

I show from theoretical aspect that the current-induced spin torques in magnetic topological materials are influenced and occasionally enhanced due to their band topology. After reviewing the current status of theoretical and experimental studies on magnetic topological materials, I will introduce some of my recent works. From the general point of view, I first propose that the momentum-space topology gives rise to an "intrinsic" contribution to the spin torques, which is robust against disorder and thermal fluctuation. In particular, I point out the intrinsic torque exerting on magnetic textures, such as domain walls (DWs), which we call the "topological Hall torque (THT)". Experimental measurability of the THT in the metallic ferromagnet SrRuO, in connection with the temperature dependence in its anomalous Hall effect, will also be mentioned.