Possible topological states in two dimensional Kagome ferromagnet MnGe

Abstract

From first principles computation, we propose hexagonal MnGe as a ferromagnetic Kagome candidate. As for three dimensional (3D) MnGe, the nearest, next-nearest and next-next-nearest magnetic exchange interaction parameters are respectively estimated to be 0.4 meV, 7.8 meV and 1.8 meV within the Heisenberg model while the calculated Curie temperature Tc is approaching 115 K based on Monte Carlo (MC) simulation. As for two dimensional (2D) MnGe monolayer, the spin-orbit coupling (SOC) would bring in a tiny gap (~ 1.9 meV) at the Dirac nodes and quantum anomalous Hall (QAH) effect, characterized by the chiral edge states and nonzero Chern number (C = 1). Moreover, the Dirac points can be tuned to the fermi level EF by 1.5 electrons doping or 3.3% compressive biaxial strain. Besides, possible synthetic scheme as well as the mechanical, dynamical and thermal stability are confirmed for both bulk and monolayer MnGe. Thus our work provides a promising Kagome ferromagnet to study intriguing topological physics associated with Dirac fermions towards spintronics application.