Minimal electronic models for superconducting BiS$_2$ layers

Hidetomo Usui; Katsuhiro Suzuki; Kazuhiko Kuroki

doi:10.1103/physrevb.86.220501

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arXiv · 1207.3888

Minimal electronic models for superconducting BiS$_2$ layers

Hidetomo Usui·Katsuhiro Suzuki·Kazuhiko Kuroki

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Abstract

We construct minimal electronic models for a newly discovered superconductor LaO$_{1-x}$F$_x$BiS$_2$ ($T_c=$ 10.6K) possessing BiS$_2$ layers based on first principles band calculation. First, we obtain a model consisting of two Bi $6p$ and two S $3p$ orbitals, which give nearly electron-hole symmetric bands. Further focusing on the bands that intersect the Fermi level, we obtain a model with two $p$ orbitals. The two bands (per BiS$_2$ layer) have quasi-one-dimensional character with a double minimum dispersion, which gives good nesting of the Fermi surface. At around $x\sim 0.5$ the topology of the Fermi surface changes, so that the density of states at the Fermi level becomes large. Possible pairing states are discussed.

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Hidetomo Usui, Katsuhiro Suzuki, Kazuhiko Kuroki. 2012-12-05. Minimal electronic models for superconducting BiS$_2$ layers. https://doi.org/10.1103/physrevb.86.220501

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