Karmakar B, Pellegrini V, Pinczuk A, Pfeiffer LN, West KW. First-order quantum phase transition of excitons in quantum Hall bilayers.
PHYSICAL REVIEW LETTERS 2009;
102:036802. [PMID:
19257378 DOI:
10.1103/physrevlett.102.036802]
[Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2008] [Indexed: 05/27/2023]
Abstract
We show that the quantum phase transformation between compressible metallic and incompressible excitonic states in the coupled bilayers at total Landau level filling factor nuT=1 becomes discontinuous (first order) by impacts of different terms of the electron-electron interactions that prevail on weak residual disorder. The evidence is based on precise determinations of the excitonic order parameter by inelastic light scattering measurements close to the phase boundary. While there is marked softening of low-lying excitations, our experiments underpin the roles of competing order parameters linked to quasiparticle correlations in removing the divergence of quantum fluctuations.
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