Ballistic transport in extended Datta-Das spin field effect transistors

The model of the Datta-Das spin field effect transistor [S. Datta, B. Das, Appl. Phys. Lett. 56 (1990) 665] is extended in several respects: (1) the Rashba effect and Dresselhaus effect coexist; (2) the incoming and outgoing leads are both ferromagnetic; (3) the interfacial scattering and band mismatch are taken into account. By using the Griffith boundary conditions, the transmission coefficients and, thus, the Landauer-Büttiker conductance are obtained analytically. The transmission probability and conductance of the spin field effect transistor are studied in detail.