Spin chirality, berry phase and anomalous Hall effect in frustrated ferromagnets

摘要: Abstract Quantum transport is very sensitive to the interference of quantal phase. The Aharanov–Bohm effect one most prominent examples it. In ferromagnets, non-coplanar spin structure gives rise analogous due chirality, i.e. solid angle subtended by spins. This contributes anomalous Hall at low temperatures. We present here theoretical results on two-dimensional Kagome lattice, which a typical example flat-band ferromagnet. Berry phase induced tilting spins opens band gap, and quantized conductance σxy=±e2/h realized without external magnetic field. also discuss observed in three-dimensional metallic pyrochlore ferromagnets R2Mo2O7 (R=Nd, Sm, Gd).