Magnetic competition in topological kagome magnets

Abstract

Magnetic competition in topological kagome magnets is studied by incorporating the spin-orbit coupling, anisotropic Hund coupling and spin exchange into a tight-binding electron dynamics in the kagome lattice. Using the Bogoliubov variational principle we find the stable phases at zero and finite temperatures. At zero temperature and in the strong Ising-Hund coupling regime, a magnetic tunability from the out-of-plane ferromagnetism to the in-plane antiferromagnetism is achieved through a universal property of the critical in-plane Hund coupling. At low temperature the out-of-plane ferromagnetism is stable until a finite crossing temperature. Above the crossing temperature the in-plane antiferromagnetism is stable, but the magnetization of the out-of-plane ferromagnetism still survives. This suggests a metastable coexistence of these magnetic phases in a finite temperature range. A large anomalous Hall conductance is observed in the Ising-Hund coupling limit.

Magnetic topological phases in the double exchange model with spin–orbit coupling

“…The double exchange is the principal mechanism for magnetization in a number of magnetic materials, for example in manganites, and especially in colossal magnetoresistant materials [17][18][19]. Incorporating the SOC into the double exchange processes, one can study the interplay between magnetism and topology [12][13][14][15][16][20][21][22]. This interplay could shed a light on the physical properties of MTIs.…”