Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong.
Phys Rev Lett. 2009 Dec 4;103(23):236402. doi: 10.1103/PhysRevLett.103.236402.
In this Letter, we study the effect of nonmagnetic impurities on two-band superconductors by deriving the corresponding Ginzburg-Landau equation. Depending on the strength of (impurity-induced) interband scattering, we find that there are two distinctive regions where the superconductors behave very differently. In the strong impurity-induced interband scattering regime T(c) << tau(t)(-1), where tau(t) approximately mean lifetime an electron stays in one band, the two-band superconductor behaves as an effective one-band dirty superconductor. In the other limit T(c) > or = tau(t)(-1), the dirty two-band superconductor is described by a network of frustrated two-band superconductor grains connected by Josephson tunneling junctions, and the Anderson theorem breaks down.
在这封信中，我们通过推导相应的吉布斯-朗道方程来研究非磁性杂质对双带超导体的影响。根据（杂质诱导的）带间散射的强度，我们发现存在两个截然不同的区域，其中超导体的行为非常不同。在强杂质诱导的带间散射区域 T(c) << tau(t)(-1) 中，其中 tau(t) 大约是电子在一个能带中停留的平均寿命，双带超导体表现为有效单带脏超导体。在另一个极限 T(c) >= tau(t)(-1) 中，脏双带超导体由通过约瑟夫森隧道结连接的受挫双带超导体颗粒网络描述，而安德森定理失效。
