Mott transition from a diluted exciton gas to a dense electron-hole plasma in a single V-shaped quantum wire

TL;DR

This study investigates the gradual Mott transition from an exciton gas to an electron-hole plasma in a V-shaped quantum wire, revealing how carrier density influences many-body interactions and the role of disorder.

Contribution

It provides systematic experimental evidence of the Mott transition in a single quantum wire, highlighting the gradual nature and disorder effects on the transition.

Findings

Transition occurs gradually from exciton gas to electron-hole plasma.

Degeneracy of electron-hole plasma at n aX = 0.8.

Non-linear effects depend on disorder and localization.

Abstract

We report on the study of many-body interactions in a single high quality V-shaped quantum wire by means of continuous and time-resolved microphotoluminescence. The transition from a weakly interacting exciton gas when the carrier density n is less than 10^5 cm^-1 (i.e. n aX < 0.1, with aX the exciton Bohr radius), to a dense electron-hole plasma (n > 10^6 cm^-1, i.e. n aX > 1) is systematically followed in the system as the carrier density is increased. We show that this transition occurs gradually : the free carriers first coexist with excitons for n aX > 0.1, then the electron-hole plasma becomes degenerate at n aX = 0.8. We also show that the non-linear effects are strongly related to the kind of disorder and localization properties in the structure especially in the low density regime.