A variational Monte Carlo study of exciton condensation

International Conference on Strongly Correlated Electron Systems 2014

Watanabe, Hiroshi^1 ; Seki, Kazuhiro^2 ; Yunoki, Seiji^1,2,3

Computational Quantum Matter Research Team, RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama

351-0198, Japan^1

Computational Condensed Matter Physics Laboratory, RIKEN, Saitama

351-0198, Japan^2

Computational Materials Science Research Team, RIKEN Advanced Institute for Computational Science (AICS), Hyogo, Kobe

650-0047, Japan^3

关键词: Band insulators;    BCS-BEC crossover;    Excitonic insulator;    Real-space;    Square lattices;    Two-band Hubbard model;    Variational Monte Carlo;    Variational Monte Carlo method;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/592/1/012097/pdf
DOI  :  10.1088/1742-6596/592/1/012097

来源: IOP

【 摘 要 】

Exciton condensation in a two-band Hubbard model on a square lattice is studied with variational Monte Carlo method. We show that the phase transition from an excitonic insulator to a band insulator is induced by increasing the interband Coulomb interaction. To examine the character of the exciton condensation, the exciton pair amplitudes both in k-space and in real space are calculated. Using these quantities, we discuss the BCS-BEC crossover within the excitonic insulator phase.