Revealing the Empty-State Electronic Structure of Single-Unit-Cell FeSe/SrTiO3

Dennis Huang; Can-Li Song; Tatiana A Webb; Shiang Fang; Cui-Zu Chang; Jagadeesh S Moodera; Efthimios Kaxiras; Jennifer E Hoffman

doi:10.1103/PhysRevLett.115.017002

Revealing the Empty-State Electronic Structure of Single-Unit-Cell FeSe/SrTiO3

Phys Rev Lett. 2015 Jul 3;115(1):017002. doi: 10.1103/PhysRevLett.115.017002. Epub 2015 Jul 2.

Authors

Dennis Huang¹, Can-Li Song¹, Tatiana A Webb^{1

2}, Shiang Fang¹, Cui-Zu Chang³, Jagadeesh S Moodera^{3

4}, Efthimios Kaxiras^{1

5}, Jennifer E Hoffman¹

Affiliations

¹ Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA.
² Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada.
³ Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
⁴ Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
⁵ School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA.

PMID: 26182116
DOI: 10.1103/PhysRevLett.115.017002

Abstract

We use scanning tunneling spectroscopy to investigate the filled and empty electronic states of superconducting single-unit-cell FeSe deposited on SrTiO3(001). We map the momentum-space band structure by combining quasiparticle interference imaging with decay length spectroscopy. In addition to quantifying the filled-state bands, we discover a Γ-centered electron pocket 75 meV above the Fermi energy. Our density functional theory calculations show the orbital nature of empty states at Γ and explain how the Se height is a key tuning parameter of their energies, with broad implications for electronic properties.