Evidence for charging effects in CdTe/CdMgTe quantum point contacts

Abstract

Here we report on fabrication and low-temperature magnetotransport measurements of quantum point contacts patterned from a novel two-dimensional electron system---CdTe/CdMgTe modulation doped heterostructure. From the temperature and bias dependence we ascribe the reported data to evidence for a weakly bound state which is naturally formed inside a CdTe quantum constriction due to charging effects. We argue that the spontaneous introduction of an open dot is responsible for replacement of flat conductance plateaus by quasiperiodic resonances with amplitude less than $2{e}^{2}/h$, as found in our system. Additionally, below 1 K a pattern of weaker conductance peaks, superimposed upon wider resonances, is also observed.