Origin of pressure-induced anomalies in the nodal-line ferrimagnet Mn$_3$Si$_2$Te$_6$

Abstract

A pressure-induced insulator-to-metal transition (IMT) has recently been discovered in the nodal-line ferrimagnet Mn$_3$Si$_2$Te$_6$. The electronic phase transition is accompanied by anomalies in the magnetic ordering temperature and the anomalous Hall conductivity, which peak at or near the critical pressure of the IMT. We perform density functional theory (DFT) calculations as a function of pressure to establish the connection between the IMT and the magnetic anomalies in Mn$_3$Si$_2$Te$_6$. We extract Heisenberg Hamiltonians as a function of pressure based on our DFT calculations. Our classical Monte Carlo simulations for these Hamiltonians yield ordering temperatures and magnetic ordering patterns, in agreement with the experimental data. Although we can accurately explain the evolution of magnetism with pressure, it seems that the anomalous Hall conductivity in Mn$_3$Si$_2$Te$_6$ can only be accounted for by extrinsic contributions or moderate electron doping of the samples in the experiment.