In-plane magnetic-field effect on transport properties of the chiral edge state in a quasi-three-dimensional quantum well structure

The transport properties of a quasi-three-dimensional, 200-layer quantum-well structure are investigated at integer filling in the quantum Hall state, concomitant with the chiral edge state condition. We find that the transverse magnetoresistance $R_{\mathrm{xx}},$ the Hall resistance $R_{\mathrm{xy}},$ and the vertical resistance $R_{\mathrm{zz}}$ all follow a similar behavior with both temperature and in-plane magnetic field. A general characteristic of the influence of increasing in-plane field $B_{\mathrm{in}}$ is that the quantization condition first improves, but above a critical value $B_{\mathrm{in}}^C,$ the quantization is systematically removed. We consider the interplay of the chiral edge state transport and the bulk (quantum Hall) transport properties. This mechanism may arise from the competition of the cyclotron energy with the superlattice band-structure energies. A comparison of the results with existing theories of the chiral edge state transport with in-plane field is also discussed.