Temperature dependence of Yb valence in the sub-surface of YbB12(001)

International Conference on Strongly Correlated Electron Systems 2016

Hagiwara, Kenta^1 ; Takeno, Yusuke^1 ; Ohtsubo, Yoshiyuki^1,2 ; Yukawa, Ryu^3 ; Kobayashi, Masaki^3 ; Horiba, Koji^3 ; Kumigashira, Hiroshi^3 ; Rault, Julien^4 ; Le Fevre, Patrick^4 ; Bertran, Francois^4 ; Taleb-Ibrahimi, Amina^4,5 ; Iga, Fumitoshi^6 ; Kimura, Shin-Ichi^1,2

Department of Physics, Graduate School of Science, Osaka Unviersity, Toyonaka

560-0043, Japan^1

Graduate School of Frontier Biosciences, Osaka University, Suita

565-0871, Japan^2

Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba

305-0801, Japan^3

Synchrotron SOLEIL, Saint-Aubin-BP 48, Gif sur Yvette

F-91192, France^4

UR1/CNRS-Synchrotron SOLEIL, Saint-Aubin, Gif sur Yvette

F-91192, France^5

College of Science, Ibaraki University, Mito

310-8512, Japan^6

关键词: Clean surfaces;    Cleaning methods;    Kondo insulators;    Photoelectron spectrum;    Sub-surfaces;    Surface electronic structures;    Temperature dependence;    Temperature dependent;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/807/1/012003/pdf
DOI  :  10.1088/1742-6596/807/1/012003

来源: IOP

【 摘 要 】

The typical Kondo insulator, YbB12, is a candidate of topological Kondo insulators. To clarify the surface electronic structure of not only bulk but also surface by photoelectron measurements, we developed a method to obtain a clean surface of YbB12(001) by annealing at 1650 K in an ultra-high vacuum. By surface-sensitive photoelectron measurements, it was known that the surface consists of only B atoms without Yb. In the sub-surface region, Yb atoms exist and the temperature dependence of the valence agrees with those of previous HAXPES results. Here we report the cleaning method to obtain well-defined YbB12(001) surfaces and the temperature-dependent Yb valence obtained from Yb 3d core-level and valence photoelectron spectra.