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
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Xuxin Huang
- Stanford University