Probing fractional quantum Hall effect by photoluminescence

TL;DR

This paper provides a theoretical framework for understanding photoluminescence signals in fractional quantum Hall states, revealing how PL intensity peaks at specific fillings and can inform about exciton and trion binding energies.

Contribution

It introduces a novel theoretical analysis of photoluminescence in FQH states, explaining how PL intensity relates to correlations and temperature, which was previously not well understood.

Findings

PL intensity peaks at Jain fillings at finite temperatures

Temperature dependence reveals exciton and trion binding energies

Implications for PL experiments in quantum wells and TMD bilayers

Abstract

The recent discovery of fractional quantum anomalous Hall (FQAH) states - fractional quantum Hall (FQH) states realized without an external magnetic field - in twisted transition-metal dichalcogenide (TMD) bilayers represents a significant development in condensed matter physics. Notably, these states were first observed via photoluminescence (PL) spectroscopy. Surprisingly, a general theoretical understanding of PL is not available even for the standard FQH states. For an ideal two-dimensional system, the energy of the emitted photon is predicted to be independent of the correlations, but we show that the PL intensity contains valuable information. Specifically, we predict that at finite temperatures, the PL intensity peaks at the Jain fillings \nu = n/(2n \pm 1), and away from these fillings, the binding energies of the composite-fermion excitons and trions can be deduced from the temperature dependence of the intensity. We discuss implications for PL experiments in semiconductor quantum wells and twisted TMD bilayers.