Berry Phase Effect on Exciton Transport and Bose Einstein Condensate

TL;DR

This paper explores how Berry phase influences exciton transport and Bose-Einstein condensation in semiconductor quantum wells, predicting novel spin-dependent topological effects and vortex phenomena.

Contribution

It reveals a momentum-space gauge field caused by Berry phase effects and predicts new spin-dependent transport and vortex behaviors in exciton systems.

Findings

Prediction of spin-dependent topological transport of excitons

Identification of vortex formation in exciton condensates

Discovery of a momentum-space gauge field due to Berry phase

Abstract

With exciton lifetime much extended in semiconductor quantum-well structures, their transport and Bose-Einstein condensation become a focus of research in recent years. We reveal a momentum-space gauge field in the exciton center-of-mass dynamics due to Berry phase effects. We predict spin-dependent topological transport of the excitons analogous to the anomalous Hall and Nernst effects for electrons. We also predict spin-dependent circulation of a trapped exciton gas and instability in an exciton condensate in favor of vortex formation.