Bound State and Order Parameter Mixing Effect by Nonmagnetic Impurity Scattering in Two-band Superconductors
Bound State and Order Parameter Mixing Effect by Nonmagnetic Impurity Scattering in Two-band Superconductors
复制标题
双能带超导体中非磁性杂质散射的束缚态和有序参数混合效应
DOI：
10.1143/jpsj.71.1978
复制
发表时间：
2002
影响因子：
1.7
通讯作者：
Y. Ohashi
中科院分区：
文献类型：
--
作者：
Y. Ohashi
本文研究了双带超导体中的杂质效应，着重研究了杂质散射效应。在玻恩近似下，已知带间散射混合了两个带中的序参数。特别地，在脏极限[G. Gusman：J.Phys.Chem.Solids28（1967）2327]。在本文中，我们考虑了带间散射的t -矩阵近似超过玻恩近似在以前的工作。我们表明，虽然带间散射是负责的混合效果，这种效果变得很弱时，带间散射变得很强。在强带间散射极限下，超导态密度恢复为对应于两个序参量的双能隙结构。我们还表明，束缚态出现在周围的一个带间散射势的相位依赖于一个电子杂质。
We investigate nonmagnetic impurity effects in two-band superconductors, focusing on the effects of interband impurity scatterings. Within the Born approximation, it is known that interband scatterings mix order parameters in the two bands. In particular, only one averaged energy gap appears in the excitation spectrum in the dirty limit [G. Gusman: J. Phys. Chem. Solids 28 (1967) 2327]. In this paper, we take into account the interband scattering within the t -matrix approximation beyond the Born approximation in the previous work. We show that, although the interband scattering is responsible for the mixing effect, this effect becomes weak when the interband scattering becomes very strong. In the strong interband scattering limit, a two-gap structure corresponding to two order parameters recovers in the superconducting density of states. We also show that a bound state appears around a nonmagnetic impurity depending on the phase of interband scattering potential.