Magnetic-field induced subband mixing in tunnel-coupled quantum point contacts: Transport spectroscopy and numerical modelling

We study the dependence of subband energies of a double quantum point contact on an external magnetic field applied in the transport direction. The comparison with experimental magnetotransport data allows us to identify the conditions for the modulation of anticrossing gaps and to map the subband spectra with the measured transconductance. The effect of an asymmetry of the two quantum point contacts is also investigated. (c) 2007 Elsevier B.V. All rights reserved.