Effect of charged donor correlation and Wigner liquid formation on the transport properties of a two-dimensional electron gas in modulation delta-doped heterojunctions

摘要

We report on the calculation of transport properties of a quasi-two-dimensional electron gas (2DEG) positioned at a GaAs/AlxGa1-xAs interface separated by a thin spacer layer from a moderately 6-doped and only partially depleted donor layer. We show that due to a correlated distribution of charge on the donors the mobility of the 2DEG increases significantly against the case without correlations. The pair correlation function of charged (classical) donors is calculated by Monte Carlo simulations. The Boltzmann equation is solved for a degenerate 2DEG at the interface assuming the scattering on the charged donors in the 6 layer as the dominant-scattering mechanism. At low temperatures in the limit of the large filling factor of the donor layer the Wigner condensation is observed and a Bragg-like interference effect on the Wigner lattice is reported. Localization in the 2DEG disturbs the effects at the 2D electron concentration n(e)(2)<10(10) cm(-2). An improved structure for experimental studies is proposed. [SO0163-1829(99)01212-6]. [References: 18]