Diffusion and phase diagram of an electron-hole bilayer: A molecular dynamics study

Abstract

Molecular dynamics simulations of a classical, symmetric electron-hole bilayer for various values of the coupling strength $\ensuremath{\Gamma}$ and interlayer separation distance $d$ have been performed. We have analyzed the pair correlation functions, the static structure factor, and the diffusion coefficient in this study. As $d$ is decreased, diffusion goes through a minimum and then increases very rapidly; its behavior at small $d$ can be attributed to the formation of stable, weakly interacting electron-hole dipoles. We have constructed the phase diagram in the $\ensuremath{\Gamma}\text{\ensuremath{-}}d$ plane based on the amplitude of the main peak of the intralayer static structure factor and the diffusion coefficient. It is found that a solid phase is not possible for $d$ less than about 0.5 for any $\ensuremath{\Gamma}$, nor for $\ensuremath{\Gamma}$ less than about 100 for any $d$. Our phase diagram, obtained using a different methodology, is in good agreement with the one in the literature.