Spin-orbit terms in multi-subband electron systems: A bridge between bulk and two-dimensional Hamiltonians

TL;DR

This paper investigates how spin-orbit interactions in multi-subband quasi-two-dimensional electron systems originate from bulk properties and emphasizes the importance of measuring inter-subband matrix elements for a complete understanding.

Contribution

It introduces a method to analyze the descent of bulk spin-orbit terms into multi-subband systems and proposes magnetic field tuning to measure inter-subband spin-orbit interactions.

Findings

Single subband measurements are insufficient for full characterization.

Inter-subband spin-orbit matrix elements are crucial for complete understanding.

Magnetic field tuning can experimentally access inter-subband spin-orbit effects.

Abstract

We analyze the spin-orbit terms in multi-subband quasi-two-dimensional electron systems, and how they descend from the bulk Hamiltonian of the conduction band. Measurements of spin-orbit terms in one subband alone are shown to give incomplete information on the spin-orbit Hamiltonian of the system. They should be complemented by measurements of inter-subband spin-orbit matrix elements. Tuning electron energy levels with a quantizing magnetic field is proposed as an experimental approach to this problem.