Coupled one-dimensional subbands in in-plane magnetic fields

The conductance of a quantum point contact fabricated on a wide two-dimensi onal (2D) electron gas has been measured as a function of the split-gate vo ltage for different magnetic fields applied in the plane of the electron ga s. Ln this quantum point contact 1D subbands originating from the two later al confinement directions are occupied. The magnetic-field dependence of th e 1D subbands is found to differ for the two considered field directions al ong and perpendicular to the direction of the current how. The results are explained assuming parabolic confinement in two directions and considering the field-induced energy shift in the constriction as well as a held-depend ent density of states in the electron gas. (C) 1998 Elsevier Science B.V. A ll rights reserved.