Temperature-dependent magnetotransport properties for systems of few quantum wires

Abstract

We have investigated temperature-dependent magnetotransport properties of quantum wires fabricated on high mobility GaAsGaAlAs modulation doped heterostructures. Laser holography and optical lithography were used to define multiple quantum wire systems with 40 wires in parallel. These “few wire systems” turn out to have the best signal to noise ratio for systematic magnetic depopulation and magnetophonon resonance measurements. In the examined temperature range between 1.9 and 160 K it was found that the 1D subband energies increase strongly with decreasing 1D electron density and the polaron mass increases with increasing 1D subband spacing. Between 100 and 160 K, magnetophonon resonance data indicate a decline of both the subband spacing and also the polaron mass with increasing temperature. This effect is most probably due to an increase of the electron concentration with increasing temperature.