Minimal electronic models for superconducting BiS2 layers
Minimal electronic models for superconducting BiS2 layers
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DOI：
10.1103/physrevb.86.220501
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发表时间：
2012-12-03
影响因子：
3.7
通讯作者：
Kuroki, Kazuhiko
中科院分区：
文献类型：
--
作者：
Usui, Hidetomo;Suzuki, Katsuhiro;Kuroki, Kazuhiko
基于第一原理能带计算，我们建立了一个新发现的具有BiS_2层的超导体LaO_1-xF_xBiS_2(T-c=10.6K)的最小电子模型。首先，我们得到了一个由两个Bi6p轨道和两个S 3p轨道组成的模型，它们给出了近乎电子-空穴对称的能带。进一步聚焦于与费米能级相交的能带，得到了一个具有两个p轨道的模型。这两个带(每个BIS2层)具有准一维特征，具有双最小色散，这使得费米面有很好的嵌套。当x接近0.5时，费米面的拓扑结构发生变化，费米能级的态密度变大。讨论了可能的配对态。
We construct minimal electronic models for a newly discovered superconductor LaO1-xFxBiS2 (T-c = 10.6 K) possessing BiS2 layers based on a 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 BiS2 layer) have a quasi-one-dimensional character with a double minimum dispersion, which gives good nesting of the Fermi surface. At around x similar to 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.