Spin effects in a confined 2DEG: Enhancement of the g-factor, spin-inversion states and their far-infrared absorption

TL;DR

This paper explores spin phenomena in a confined 2DEG, revealing how Coulomb interactions enhance the g-factor, induce spin-inversion states, and affect far-infrared absorption, with implications for understanding spin-related effects in quantum systems.

Contribution

It demonstrates the formation of spin-inversion states and the enhancement of the g-factor due to Coulomb interactions in a confined 2DEG, using Hartree-Fock approximation.

Findings

Large spin level splitting within Landau bands due to exchange interaction

Spontaneous formation of spin-inversion states at half-filled Landau bands

Far-infrared absorption signals indicating spin-inversion states

Abstract

We investigate several spin-related phenomena in a confined two-dimensional electron gas (2DEG) using the Hartree-Fock approximation for the mutual Coulomb interaction of the electrons. The exchange term of the interaction causes a large splitting of the spin levels whenever the chemical potential lies within a Landau band (LB). This splitting can be reinterpreted as an enhancement of an effective g-factor, g*. The increase of g* when a LB is half filled can be accompanied by a spontaneous formation of a static spin-inversion state (SIS) whose details depend on the system sision state (SIS) whose details depend on the system size. The coupling of the states of higher LB's into the lowest band by the Coulomb interaction of the 2DEG is essential for the SIS to occur. The far-infrared absorption of the system, relatively insensitive to the spin splitting, develops clear signs of the SIS.