Interface Contributions to the Spin-Orbit Interaction Parameters of Electrons at the (001) GaAs/AlGaAs Interface

摘要

One-body mechanisms of spin splitting of the energy spectrum of 2D electronsin a one-side doped (001) GaAs/Al$_x$Ga$_{1-x}$As quantum well have beenstudied theoretically and experimentally. The interfacial spin splitting hasbeen shown to compensate (enhance) considerably the contribution of the bulkDresselhaus (Bychkov-Rashba) mechanism. The theoretical approach is based onthe solution of the effective mass equation in a quasitriangular wellsupplemented by a new boundary condition at a high and atomically sharpheterobarrier. The model takes into account the spin-orbit interaction ofelectrons with both bulk and interfacial crystal potential having C$_{2v}$symmetry, as well as the lack of inversion symmetry and nonparabolicity of theconduction band in GaAs. The effective 2D spin Hamiltonian including both bulkand interfacial contributions to the Dresselhaus ($\alpha_{BIA}$) and Rashba($\alpha_{SIA}$) constants has been derived. The analytical relation betweenthese constants and the components of the anisotropic nonlinear $g$-factortensor in an oblique quantizing magnetic field has been found. The experimentalapproach is based, on one hand, on the detection of electron spin resonance inthe microwave range and, on the other hand, on photoluminescence measurementsof the nonparabolicity parameter. The interfacial contributions to$\alpha_{BIA}$ and $\alpha_{SIA}$ have been found from comparison with thetheory.