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