Unconventional superconductivity in the presence of long-range interactions in transition metal dichalcogenide moiré heterobilayers
摘要
Transition-metal dichalcogenide (TMD) moiré systems have recently garnered much attention as platforms for studying electron-correlation-induced effects as well as unconventional superconductivity (SC). Here we analyze the principal features of the unconventional superconducting state in a TMD moiré flat band in the strongly correlated regime and in the presence of significant intersite Coulomb repulsion as well as long-range hopping and exchange interaction terms. In our study, we use the extended versions of both the t-J-U and t-J models and apply the Gutzwiller approximation method to incorporate the effects of electron-electron interactions. We show that in the strongly correlated regime and close to half-filling, the superconducting state is strongly immune to the negative effect of the V-term on the pairing, and shows a two-dome behavior with a Mott insulating state residing at half-filling. We explain this result as originating from relatively strong renormalization of the intersite interaction terms, caused by the significant value of the onsite Coulomb repulsion. As we show, this mechanism allows the superconductivity to persist even for relatively large values of V, which are characteristic for the WS