Correlation effects in partially ionized mass asymmetric electron-hole plasmas

TL;DR

This study uses Monte Carlo simulations to explore Coulomb correlations, bound state formation, and phase transitions in dense electron-hole plasmas, highlighting the impact of mass ratio on plasma properties and crystal formation.

Contribution

It provides new insights into the effects of mass ratio on correlation phenomena, bound states, and phase transitions in electron-hole plasmas through unbiased simulations.

Findings

Identification of density-temperature regions for exciton and bi-exciton formation.

Detection of Mott transition to an electron-hole liquid at high density.

Verification of hole Coulomb crystal formation at high mass ratios.

Abstract

The effects of strong Coulomb correlations in dense three-dimensional electron-hole plasmas are studied by means of unbiased direct path integral Monte Carlo simulations. The formation and dissociation of bound states, such as excitons and bi-excitons is analyzed and the density-temperature region of their appearance is identified. At high density, the Mott transition to the fully ionized metallic state (electron-hole liquid) is detected. Particular attention is paid to the influence of the hole to electron mass ratio $M$ on the properties of the plasma. Above a critical value of about M=80 formation of a hole Coulomb crystal was recently verified [Phys. Rev. Lett. {\bf 95}, 235006 (2005)] which is supported by additional results. Results are related to the excitonic phase diagram of intermediate valent Tm[Se,Te], where large values of $M$ have been observed experimentally.