Unconventional Superconductivity in the BiS2-Based Layered Superconductor NdO0.71F0.29BiS2

Yuichi Ota; Kozo Okazaki; Haruyoshi Q. Yamamoto; Takashi Yamamoto; Shuntaro Watanabe; Chuangtian Chen; Masanori Nagao; Satoshi Watauchi; Isao Tanaka; Yoshihiko Takano; Shik Shin

doi:10.1103/PhysRevLett.118.167002

Unconventional Superconductivity in the BiS2-Based Layered Superconductor NdO0.71F0.29BiS2

Yuichi Ota, Kozo Okazaki, Haruyoshi Q. Yamamoto, Takashi Yamamoto, Shuntaro Watanabe, Chuangtian Chen, Masanori Nagao, Satoshi Watauchi, Isao Tanaka, Yoshihiko Takano, Shik Shin

DOI 10.1103/PhysRevLett.118.167002 · Physical Review Letters

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Abstract

We investigate the superconducting-gap anisotropy in one of the recently discovered BiS2-based superconductors, NdO0.71F0.29BiS2 (Tc∼5 K), using laser-based angle-resolved photoemission spectroscopy. Whereas the previously discovered high-Tc superconductors such as copper oxides and iron-based superconductors, which are believed to have unconventional superconducting mechanisms, have 3d electrons in their conduction bands, the conduction band of BiS2-based superconductors mainly consists of Bi 6p electrons, and, hence, the conventional superconducting mechanism might be expected. Contrary to this expectation, we observe a strongly anisotropic superconducting gap. This result strongly suggests that the pairing mechanism for NdO0.71F0.29BiS2 is an unconventional one and we attribute the observed anisotropy to competitive or cooperative multiple paring interactions.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
NdO0.71F0.29BiS2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	5	Pressure not reported	unknown
NdO0.71F0.29BiS2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	5	Pressure not reported	unknown
LaO1-xFxBiS2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown
NdO1-xFxBiS2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	5.6	Pressure not reported	unknown