Numerical Study of Exciton Condensation in the Bilayer Hubbard Model
Abstract: This work investigates the exciton property of the bilayer Hubbard model by using the con-strained-path Monte Carlo method. The calculated results show that when the doping density is lower than 0.08, the local exciton characterized by interlayer single particle tunneling is enhanced by the interlayer Coulomb interaction V, and the enhancement becomes stronger with decreasing the doping density. However, when the doping density is higher than 0.08, the local exciton is sup- pressed by V. This result exhibits significant differences from the published results at finite temperatures. Further analysis shows that the long-range exciton correlation function is reduced with increasing V, demonstrating that there does not exist exciton condensation in the studied model. In addition, the interlayer Coulomb interaction V is shown to have a rather weak effect on local magnetic moment.
文章引用: 梅 聪 , 吴永政 , 高 云 , 黄忠兵 (2015) 双层哈伯德模型中激子态的数值研究。 凝聚态物理学进展， 4， 70-76. doi: 10.12677/CMP.2015.42008
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