1. Observation of a Hidden Hole-Like Band Approaching the Fermi Level in K-Doped Iron Selenide Superconductor
- Author
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Sunagawa, Masanori, Terashima, Kensei, Hamada, Takahiro, Fujiwara, Hirokazu, Fukura, Tetsushi, Takeda, Aya, Tanaka, Masashi, Takeya, Hiroyuki, Takano, Yoshihiko, Arita, Masashi, Shimada, Kenya, Namatame, Hirofumi, Taniguchi, Masaki, Suzuki, Katsuhiro, Usui, Hidetomo, Kuroki, Kazuhiko, Wakita, Takanori, Muraoka, Yuji, and Yokoya, Takayoshi
- Subjects
Condensed Matter - Superconductivity - Abstract
One of the ultimate goals of the study of iron-based superconductors is to identify the common feature that produces the high critical temperature (Tc). In the early days, based on a weak-coupling viewpoint, the nesting between hole- and electron-like Fermi surfaces (FSs) leading to the so-called $s\pm$ state was considered to be one such key feature. However, this theory has faced a serious challenge ever since the discovery of alkali-metal-doped FeSe (AFS) superconductors, in which only electron-like FSs with a nodeless superconducting gap are observed. Several theories have been proposed, but a consistent understanding is yet to be achieved. Here we show experimentally that a hole-like band exists in KxFe2-ySe2, which presumably forms a hole-like Fermi surface. The present study suggests that AFS can be categorized in the same group as iron arsenides with both hole- and electron-like FSs present. This result provides a foundation for a comprehensive understanding of the superconductivity in iron-based superconductors., Comment: 15 pages, 4 figures, + supplemental material
- Published
- 2016
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