Engineering the in-plane anomalous Hall effect in Cd_3As_2 thin films

We predict two topological phase transitions for cadmium arsenide (Cd3As2) thin films under in-plane magnetic field, taking advantage of a four-band k· p model and effective g factors calculated from first principles. Film thickness, growth direction and in-plane Zeeman coupling strength can all serve as control parameters to drive these phase transitions. For (001) oriented Cd3As2 thin films, a two dimensional Weyl semimetal phase protected by C_2z𝒯 symmetry can be realized using an in-plane magnetic field, which has recently been reported in our companion paper. We then put forth two pathways to achieve in-plane anomalous Hall effects (IPAHE). By either introducing a trigonal warping term or altering the growth orientation, the emergent C_2z𝒯 symmetry can be broken. Consequently, in the clean limit and at low temperatures, quantized Hall plateaus induced by in-plane Zeeman fields become observable.