1. Inhomogeneous charge distribution in a self-doped EuFBiS2 superconductor
- Author
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Kensei Terashima, Takashi Mizokawa, Takanori Wakita, Eugenio Paris, Ryuji Higashinaka, Alessio Giampietri, Joe Kajitani, T. Sugimoto, Tatsuma D. Matsuda, Takayoshi Yokoya, Y. Aoki, A. Barinov, and Naurang L. Saini
- Subjects
Superconductivity ,Mesoscopic physics ,Valence (chemistry) ,Materials science ,BiS2-based superconductors ,Condensed matter physics ,self-doping ,Doping ,Charge density ,Fermi surface ,electronic structure ,space resolved ARPES ,Condensed Matter::Superconductivity ,BiS2-based superconductors, self-doping, space resolved ARPES, electronic structure ,Condensed Matter::Strongly Correlated Electrons ,Density functional theory ,Stoichiometry - Abstract
Stoichiometric ${\mathrm{EuFBiS}}_{2}$ with mixed valent Eu shows self-doped superconductivity at low temperatures due to the Eu-to-Bi charge transfer. The metallic/nonmetallic bistability of the ${\mathrm{BiS}}_{2}$ layer can couple with the valence fluctuation of Eu and provide a highly susceptible electronic state. Here, we report space-resolved photoemission measurements on ${\mathrm{EuFBiS}}_{2}$ revealing an inhomogeneous charge distribution with the coexistence of metallic and nonmetallic phases at mesoscopic length scales. Angle-resolved photoemission measurements using a submicron beam size have confirmed a clear Fermi surface around the zone boundaries in the metallic region, typically observed in a doped system, while it can be hardly seen in the nonmetallic region. Density functional theory calculations suggest that the out-of-plane S atom position in the structure is one of the important factors for the self-doping in this material.
- Published
- 2019