AlAs quantum wells: Transport properties of the two-dimensional electron gas

We present a theory of the transport properties at zero temperature of the electron gas in AlAs. The two-dimensional electron gas in AlAs has a valley degeneracy g(v)=1 for a quantum well width L < L-c=55 A and a valley degeneracy of g(v)=2 for L > L-c. We calculate the mobility for interface-roughness scattering and for impurity scattering. In addition we discuss the single-particle relaxation time (Dingle temperature) and the magnetoresistance in a parallel magnetic field. We discuss how transport measurements can be used to get information about microscopic parameters of disorder and many-body effects. Experimental results obtained for the mobility, the magnetoresistance, and the metal-insulator transition are discussed and compared with our theory. (C) 2007 American Institute of Physics.