Abstract:

In this talk, I will cover two topics related to the kagome magnets, one is on the electric and thermal transport properties and the other is on the all-electric switching of non-collinear anti-ferromagnetism.

The Wiedemann-Franz law and Mott relation are textbook paradigms on the ratios of the thermal and thermoelectric to electrical conductivity, respectively. Deviations from them usually reveal intriguing phases of matter. The topological kagome magnets TbMn6Sn6 and Mn3Ge show confusingly opposite derivations in the Hall measurement. By theoretically considering the topological and disorder corrections, we find the dominance of the topological correction in the experiments. More importantly, we derive analytic correction formulas, which can universally capture the two opposite experiments with the chemical potential as the only parameter.

The non-collinear antiferromagnet Mn3Sn have attracted extensive interests, because of its anti-ferromagnetic advantages of ultrafast spin dynamics and large anomalous Hall effect resulting from the Weyl fermion nature. However, the dynamics of its all-electrical control is not completely clear. We simulate the switching of Mn3Sn using a pure electric current. Our simulations reveal the role of Mn3Sn itself in terms of current-induced intrinsic non-collinear spin-orbit torques, instead of the spin-orbit coupling form heavy metals in the previous works.

Our theories will be helpful for future explorations on the magnetic topological matter.