Wigner Supersolid of Excitons in Electron-Hole Bilayers

ORAL

Abstract

Bilayer electron-hole systems, where carriers in one layer are electrons and carriers in the other are holes, are expected to undergo Bose-Einstein condensation of excitons when the layer separation $d$ is much smaller than the interparticle distance $r_s a_B$ within each layer. We show, based on general principles, that there are two distinct ground states in this regime. The first, a uniform Bose condensate of excitons, has been studied in the literature. We predict the existence of a second state, a Wigner supersolid of excitons, that occurs in the region $\sqrt{r_s}\leq d/a_B\leq r_s$. In this phase, the excitons are phase coherent but form a Wigner crystal due to dipolar repulsion. We present a qualitative phase diagram of the bilayer system, and discuss properties and possible signatures of the Wigner supersolid phase.

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Authors

  • Yogesh Joglekar

    Department of Physics, Indiana University-Purdue University Indianapolis, IUPUI

  • A. Balatsky

    CINT, T-11, Los Alamos National Laboratory, Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545, Theoretical Division, Los Alamos National Laboratory, Los Alamos National Laboratory, LANL

  • Sankar Das Sarma

    Condensed Matter Theory Center, Physics Department, University of Maryland, Condensed Matter Theory Center, Department of Physics, University of Maryland, College Park, Maryland 20742, USA, Condensed Matter Theory Center, Department of Physics, University of Maryland, College Park, MD 20742, University of Maryland, Condensed Matter Theory Center, University of Maryland, College Park, MD 20742-4111, USA, University of Maryland, College Park, CMTC, Department of Physics, University of Maryland, College Park, MD 20742, CMTC, Department of Physics, UMD, Maryland, Condensed Matter Theory Center, University of Maryland