Evidence for the Eu 4f Character of Conduction-Band Edge at the Eu2O3 Surface Studied by Scanning Tunneling Spectroscopy

SURFACE SCIENCE

卷:705

Article

Lehtio, J-P¹  Hadamek, T.²  Kuzmin, M.^1,3  Laukkanen, P.¹  Demkov, A. A.² 

[1] Univ Turku, Dept Phys & Astron, FI-20014 Turku, Finland

[2] Univ Texas Austin, Dept Phys, Austin, TX 78712 USA

[3] Russian Acad Sci, Ioffe Phys Tech Inst, St Petersburg 194021, Russia

关键词: Thin film;    Europium sesquioxide;    Electronic structure;    Band gap;    Unoccupied states;    Scanning tunneling spectroscopy;   

DOI  :  10.1016/j.susc.2020.121763

来源: Elsevier

【 摘 要 】

Effects of localized Eu 4f levels on the band gap properties of Eu2O3 have attracted significant fundamental and technological interest, and the band structure of such thin films has been thoroughly studied by photoelectron spectroscopies (T. Hadamek et al., J. Appl. Phys. 127 (2020) 074101). Here we apply a scanning tunneling spectroscopy (STS) to clarify the character of the conduction band (CB) bottom at the surface of epitaxial Eu2O3 grown on GaN(0001)/Si(111) substrates. It is shown that the CB edge is formed solely by an unoccupied Eu 4f state 0.8 eV above the Fermi level at the Eu2O3 surface and does not overlap with unoccupied Eu 5d6s states laying more than 2 eV higher than the bottom of the 4f band.

【 授权许可】

Free