On the effective models of spin-orbit coupling in a two-dimensional electron gas

K. V. Samokhin

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arXiv · 2112.12657

On the effective models of spin-orbit coupling in a two-dimensional electron gas

K. V. Samokhin

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Abstract

We use the method of invariants to derive one- and two-band effective Hamiltonians of a noncentrosymmetric two-dimensional electron gas, in the presence of magnetic field. A complete classification of the antisymmetric spin-orbit and magnetic coupling terms near the $\Gamma$ point is developed for all two-dimensional crystal symmetries. The effective Hamiltonian depends on the symmetry of the Bloch bands at the $\Gamma$ point, which is described by one of the double-valued corepresentations of the two-dimensional magnetic point group. In some bands, the spin-orbit coupling is cubic in the electron momentum and the effective Zeeman interaction is strongly anisotropic. As an example of a two-band effective Hamiltonian, we introduce a simple model of a topological insulator with the intraband and interband spin-orbit coupling and investigate its bulk and boundary properties.

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K. V. Samokhin. 2021-12-23. On the effective models of spin-orbit coupling in a two-dimensional electron gas. https://arxiv.org/abs/2112.12657

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