Sign-problem-free Quantum Monte Carlo Study of Exciton Condensation in Electron-hole Doped Hubbard Bilayer

ORAL

Abstract

The bilayer Hubbard model with electron-hole doping is an ideal platform to study exciton condensation due to spatial separation of electrons and holes which can significantly suppress recombination. However, suffering from the sign problem, a previous determinant quantum Monte Carlo(DQMC) study of the Hubbard model in this system could not arrive at an unequivocal conclusion regarding the presence of exciton condensation. Here, we develop a sign-problem-free DQMC algorithm for the bilayer Hubbard model with equal and opposite doping in the two layers. We study the competition between excitonic condensation, charge and spin order as a function of electron-hole doping and interactions away from SU(4) symmetry, the point where inter-layer and intra-layer interaction are the same. For finite electron-hole doping we find that the intra-layer Hubbard interaction enhances (π, π) exciton correlations. We also discuss the spectral function and the charge and spin excitation spectra.

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Presenters

  • Xuxin Huang

    Stanford University

Authors

  • Xuxin Huang

    Stanford University

  • Martin Claassen

    Simons Foundation Flatiron Institute, Center for Computational Quantum Physics, Simons Foundation Flatiron Institute

  • Brian Moritz

    Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, SLAC - Natl Accelerator Lab, SLAC and Stanford University, SLAC National Accelerator Laboratory, Stanford Institute for Materials and Energy Sciences, SLAC National Laboratory, SIMIS, Stanford University, Physics, Stanford University, Stanford Univ, SIMES, SLAC and Stanford University

  • Thomas Devereaux

    Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Stanford Univ, SLAC and Stanford University, SLAC National Accelerator Laboratory, SLAC - Natl Accelerator Lab, Stanford Institute for Materials and Energy Sciences, SLAC National Laboratory, Stanford University, SIMIS, Stanford University, Physics, Stanford University, SLAC National Lab and Stanford University, SIMES, SLAC and Stanford University