Direct imaging of electron transfer and its influence on superconducting pairing at FeSe/SrTiO3 interface

• DOI: 10.48550/arxiv.1701.03678
• Publication Date: 2017-01-01
• Authors: Weiwei Zhao; Mingda Li; Cui‐Zu Chang; Jue Jiang; Lijun Wu; Chao‐Xing Liu; Yimei Zhu; Jagadeesh S. Moodera; Moses H. W. Chan
• Keywords: Selenide; Iron-based superconductor

The exact mechanism responsible for the tenfold enhancement of superconducting transition temperature (Tc) in a monolayer iron selenide (FeSe) on SrTiO3(STO) substrate over that bulk FeSe, is an open issue. We present here coordinated study electrical transport and low electron energy-loss spectroscopy (EELS) measurements FeSe/STO films various thicknesses. Our EELS mapping across interface shows direct evidence band-bending caused by electrons transferred from STO to FeSe layer. were found accumulate only within first two atomic layers near substrate. results positive backgate applied particularly effective enhancing Tc while minimally changing carrier density. suggest tends 'pull' closer thus further enhances both their coupling interfacial phonons electron-electron interaction films, leading huge films.