On the theory of eigen spin states and spin-orbit interaction of quasi-two-dimensional electrons

The problem of the electron spectrum in a quasi-two-dimensional space (such as interfaces, heterostructures, and surfaces) is set up and analytically solved based on the fundamental Dirac equation. It is demonstrated that using the unitary transformation method and the method of spin invariants to solve the Dirac equation leads to identical results. The eigen bispinors of the Dirac equation are found, and the way in which their diversity arises due to the arbitrariness of the spin-quantization axis direction is demonstrated. The features of electron behavior in a parabolic quantum well are considered.