Recent insights on superconductivity of monolayer FeSe
The physics of high-temperature superconductors is governed by the interplay of the spin and charge degrees of freedom. FeSe has the simplest chemical composition among Fe-based superconductors, yet monolayer FeSe on SrTiO3 substrate reports one of the highest superconducting transition temperatures, much enhanced than bulk FeSe. We will discuss the roles of charge transfer, spin magnetic moment, and phonon coupling in monolayer FeSe. For example, one specific observation - the replica bands in the photoemission spectrum - has been taken to be of central importance as evidence of strong electron-phonon interaction. However, the essence of these spectroscopic features remains controversial. We conduct angle-resolved photoemission spectroscopy measurements on monolayer FeSe/SrTiO3 using linearly polarized photons and observe high-order replica bands derived from various Fe 3d bands, similar to those observed on bare SrTiO3. Our results provide new insights into this high-temperature superconductor.
- C. Liu, H. Shin, A. Doll, H.H. Kung, R.P. Day, B.A. Davidson, J. Dreser, G. Levy, A. Damascelli, C. Piamonteze, and K. Zou, “High-temperature superconductivity and robustness against magnetic polarization in monolayer FeSe on EuTiO3”, npj Quantum Materials 6, 85 (2021).
- C. Liu, R.P. Day, F. Li, R.L. Roemer, S. Zhdanovich, S. Gorovikov, T. Pedersen, J. Jiang, S. Lee, M. Schneider, D. Wong, P. Dosanjh, F.J. Walker, C.H. Ahn, G. Levy, A. Damascelli, G.A. Sawatzky, and K. Zou, “High-order replica bands in monolayer FeSe/SrTiO3 revealed by polarization-dependent photoemission spectroscopy”, Nature Communications 12, 4573 (2021).
Host : Prof. Changyoung Kim