Ubiquitous strong electron-phonon coupling at the interface of FeSe/SrTiO3

Chaofan Zhang; Zhongkai Liu; Zhuoyu Chen; Yanwu Xie; Ruihua He; Shujie Tang; Junfeng He; Wei Li; Tao Jia; Slavko N Rebec; Eric Yue Ma; Hao Yan; Makoto Hashimoto; Donghui Lu; Sung-Kwan Mo; Yasuyuki Hikita; Robert G Moore; Harold Y Hwang; Dunghai Lee; Zhixun Shen

doi:10.1038/ncomms14468

Ubiquitous strong electron-phonon coupling at the interface of FeSe/SrTiO₃

Nat Commun. 2017 Feb 10:8:14468. doi: 10.1038/ncomms14468.

Authors

Chaofan Zhang^{1

2}, Zhongkai Liu³, Zhuoyu Chen^{1

2}, Yanwu Xie^{1

2}, Ruihua He⁴, Shujie Tang^{1

2}, Junfeng He^{1

2}, Wei Li^{1

2}, Tao Jia^{1

2}, Slavko N Rebec^{1

2}, Eric Yue Ma^{1

2}, Hao Yan^{1

2}, Makoto Hashimoto⁵, Donghui Lu⁵, Sung-Kwan Mo⁶, Yasuyuki Hikita¹, Robert G Moore^{1

2}, Harold Y Hwang^{1

2}, Dunghai Lee⁷, Zhixun Shen^{1

2}

Affiliations

¹ Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA.
² Geballe Laboratory for Advanced Materials, Departments of Physics and Applied Physics, Stanford University, Stanford, California 94305, USA.
³ School of Physical Science and Technology, ShanghaiTech University, Shanghai 200031, China.
⁴ Department of Physics, Boston College, Chestnut Hill, Massachusetts 02467, USA.
⁵ Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA.
⁶ Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
⁷ Department of Physics, University of California at Berkeley, Berkeley, California 94720, USA.

Abstract

The observation of replica bands in single-unit-cell FeSe on SrTiO₃ (STO)(001) by angle-resolved photoemission spectroscopy (ARPES) has led to the conjecture that the coupling between FeSe electrons and the STO phonons are responsible for the enhancement of T_c over other FeSe-based superconductors. However the recent observation of a similar superconducting gap in single-unit-cell FeSe/STO(110) raised the question of whether a similar mechanism applies. Here we report the ARPES study of the electronic structure of FeSe/STO(110). Similar to the results in FeSe/STO(001), clear replica bands are observed. We also present a comparative study of STO(001) and STO(110) bare surfaces, and observe similar replica bands separated by approximately the same energy, indicating this coupling is a generic feature of the STO surfaces and interfaces. Our findings suggest that the large superconducting gaps observed in FeSe films grown on different STO surface terminations are likely enhanced by a common mechanism.

Publication types

Research Support, U.S. Gov't, Non-P.H.S.