Energy spectrum reconstruction at the edge of a two-dimensional electron system with strong spin-orbit coupling

TL;DR

This paper experimentally investigates how strong spin-orbit interaction affects the energy spectra at the edges of a 2D electron system, revealing different reconstruction mechanisms at filling factors 1 and 2.

Contribution

It provides the first experimental demonstration of simultaneous bulk and edge energy spectrum reconstruction due to spin-orbit coupling at low filling factors.

Findings

Reconstruction at ν=2 involves zeroing of the energy gap at level crossing.

Reconstruction at ν=1 involves coexistence of two quantum Hall phases with different spins.

Many-body interactions significantly influence the reconstruction at ν=1.

Abstract

We experimentally demonstrate the simultaneous reconstruction of the bulk and the edge energy spectra caused by strong spin-orbit interaction, at the two lowest filling factors $\nu=1$ and $\nu=2$ for $In_xGa_{1-x}As$ two-dimensional electron system with $x = 0.75$. The observed reconstruction is of different character at these filling factors: it is characterized by zeroing of the energy gap at the levels crossing point at $\nu=2$, while the reconstruction at $\nu=1$ goes through the coexistence of two $\nu=1$ quantum Hall phases with different spin projections. An analysis indicates a strong influence of many-body interaction on the reconstruction at $\nu=1$.