Magnetism-induced band-edge shift as mechanism for magnetoconductance in CrPS${}_4$ transistors

Transistors realized on 2D antiferromagnetic semiconductor CrPS${}_4$ exhibit large magnetoconductance, due to magnetic-field-induced changes in magnetic state. The microscopic mechanism coupling conductance and magnetic state is not understood. We identify it by analyzing the evolution of the parameters determining the transistor behavior – carrier mobility and threshold voltage – with temperature and magnetic field. For temperatures T near the Néel temperature $T_N$, the magnetoconductance originates from a mobility increase due to the applied magnetic field that reduces spin fluctuation induced disorder. For $T<<T_N$, instead, what changes is the threshold voltage, so that increasing the field at fixed gate voltage increases the density of accumulated electrons. The phenomenon is explained by a conduction band-edge shift correctly predicted by \emph{ab-initio} calculations. Our results demonstrate that the bandstructure of CrPS${}_4$ depends on its magnetic state and reveal a mechanism for magnetoconductance that had not been identified earlier.