Evidence of the Coulomb gap observed in an InAs inserted In0.53Ga0.47As/In0.52Al0.48As heterostructure

We report studies of the in-plane magneto-transport properties of a 2DEG in an InAs inserted InGaAs/InAlAs heterostructure with a DC bias voltage. Temperature dependent zero-bias reduction of the longitudinal resistance was observed when high magnetic field is applied along the sample growth direction. We interpret the observed resistance reduction as the result of a Coulomb gap existing at the Fermi level of the 2DEG.