报告题目 (Title)：Mottness physics in Nb3X8 (X=Cl, Br, I)（Nb3X8 (X=Cl, Br, I)中的莫特物理）
报告人 (Speaker)：蒋坤 研究员（中国科学院物理研究所）
报告时间 (Time)：2022年9月21日(周三) 10:00-12:00
Recently, the 2-dimensional van der Waals materials Nb3Cl8 was found to be a Mott insulator. In this talk, we will discuss the correlation physics in Nb3X8 (X=Cl, Br, I). We find that the monolayers Nb3X8 are ideal systems close to the strong correlation limit. They can be described by a half-filled single band Hubbard model in which the ratio between the Hubbard, U, and the bandwidth, W, U/W ≈ 5 ∼ 10. Both Mott and magnetic transitions of the material are calculated by the slave boson mean field theory. Doping the Mott state, a dx2−y2+idxy superconducting pairing instability is found. We also construct a tunable bilayer Hubbard system for two sliding Nb3X8 layers. The bilayer system displays a crossover between the band insulator and Mott insulator.