Theoretical model for negative giant magnetoresistance in ultra-high-mobility 2D electron systems

摘要

We report on theoretical studies of the recently discovered negative giantmagnetoresistance in ultraclean two-dimensional electron systems at lowtemperatures. We adapt a transport model to a ultraclean scenario and calculatethe elastic scattering rate (electron-charged impurity) in a regime where theLandau level width is much smaller than the cyclotron energy. We obtain thatfor low magnetic fields the scattering rate and, as a consequence, thelongitudinal magnetoresistance dramatically drop because of the small densityof states between Landau levels. We also study the dependence of this strikingeffect on temperature and an in-plane magnetic field.