Effective interaction potential and superfluid-solid transition of spatially indirect excitons

TL;DR

This paper derives an effective interaction potential for spatially indirect excitons and investigates their phase transitions, including crystallization and superfluidity, revealing limitations of the dipole model in quantum wells.

Contribution

The study introduces a new effective interaction potential for indirect excitons and applies path integral Monte Carlo to analyze phase transitions, highlighting inaccuracies of the dipole model.

Findings

Exciton crystallization occurs at specific densities.

Superfluid fraction vanishes upon crystallization.

Dipole model is inadequate for quantum well structures.

Abstract

Using an adiabatic approximation we derive an effective interaction potentially for spatially indirect excitons. Using this potential and path integral Monte Carlo simulations we study exciton crystllization and the quantum melting phase transition in a macroscopic system of 2D excitons. Furthermore, the superfluid fraction is calculated as a function of density and shown to vanish upon crystallization. We show that the commonly used dipole model fails to correctly describe indirect excitons in quantum well structures.