Effect of Hubbard U on the Electronic Properties of Monolayer FeSe/SrTiO3(001) Superconductor
Recent studies identified some factors that contribute to the enhancement of Tc in monolayer FeSe/STO superconductor. It has been claimed that electron doping and electron-phonon coupling play a crucial role in high-Tc superconductivity. However, electron doping and electron-phonon mechanism alone cannot fully explain the high-Tc of monolayer FeSe/STO. In this study, we introduce another factor, the Hubbard U correction, and investigate its effect. The electronic structure calculations on single-layer FeSe grown on STO using density functional theory with Hubbard U (DFT+U) is presented. It is found that the Hubbard U suppresses the hole-like band at the Brillouin zone center leading to an electronic structure that resembles the experimental ARPES data. This suggests that electron correlation in monolayer FeSe/STO system plays a crucial role in the origin of high-Tc superconductivity.
Prof. Kazuo Umemura
N. J. P. Jacosalem and L. C. C. Ambolode II, "Effect of Hubbard U on the Electronic Properties of Monolayer FeSe/SrTiO3(001) Superconductor", Materials Science Forum, Vol. 916, pp. 38-42, 2018