Tuning of the Gap in a Laughlin-Bychkov-Rashba Incompressible Liquid

TL;DR

This paper investigates how Bychkov-Rashba spin-orbit interaction affects the Laughlin state in quantum Hall systems, showing that it can significantly increase the quasiparticle-quasihole gap and potentially tune phase transitions.

Contribution

It demonstrates that experimentally accessible spin-orbit coupling can enhance the incompressible liquid state's stability and modify quantum Hall gaps, offering a new tuning mechanism.

Findings

Spin-orbit interaction increases the quasiparticle-quasihole gap by up to 25%.

Enhancement of the gap is significant at filling factors 1/5 and 1/7.

Potential to tune liquid-solid transitions to lower densities via SO coupling.

Abstract

We report on our investigation of the influence of Bychkov-Rashba spin-orbit interaction (SOI) on the incompressible Laughlin state. We find that experimentally obtainable values of the spin-orbit coupling strength can induce as much as a 25% increase in the quasiparticle-quasihole gap Eg at low magnetic fields in InAs, thereby increasing the stability of the liquid state. The SOI-modulated enhancement of Eg is also significant for filling factors 1/5 and 1/7, where the FQH state is usually weak. This raises the intriguing possibility of tuning, via the SO coupling strength, the liquid to solid transition to much lower densities.