Novel excitonic states in quantum Hall systems: Bound states of spin waves and a valence band hole

TL;DR

This paper predicts new excitonic states in quantum Hall systems where valence holes bind with spin waves, revealing novel many-body interactions and potential effects on photoluminescence near filling factor nu=1.

Contribution

It introduces the concept of valence holes forming bound states with spin waves, analogous to skyrmions, in quantum Hall systems, expanding understanding of excitonic complexes.

Findings

Valence holes can bind with spin waves to form excitonic complexes.

Repulsive interactions at nu<=1 influence photoluminescence.

At nu>=1, attractive interactions may lead to different phenomena.

Abstract

If the Zeeman energy is small, the lowest energy excitations of a two dimensional electron gas at filling factor nu=1 are spin waves (spin flip excitations). At nu slightly larger (smaller) than unity, reversed spin electrons (spin holes) can form bound states with K spin waves that are known as skyrmions, S_K^- (antiskyrmions, S_K^+). It is suggested in this work that a valence hole can also bind K spin waves to form an excitonic complex X_K^+, analogous to the S_K^+. One spin hole of the S_K^+ is simply replaced by the valence hole. At nu<=1, a small number of S_K^+'s are present before introduction of the valence hole. The (S_K^+)-(X_K^+) repulsion leads to correlations and photoluminescence similar to those of a dilute electron-(charged-exciton) (e-X^-) system at nu<=1/3. At nu>=1, the (S_K^-)-(X_K^+) attraction can potentially lead to different behavior.