Superconductivity in non-centrosymmetric materials
Superconductivity in non-centrosymmetric materials
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DOI：
10.1016/j.physc.2015.02.016
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发表时间：
2015-07-15
影响因子：
1.7
通讯作者：
Podloucky, R.
中科院分区：
文献类型：
--
作者：
Kneidinger, F.;Bauer, E.;Podloucky, R.
在没有晶体结构的反转对称性的情况下，超导性基本上由分裂费米表面并去除电子的自旋简并的Rashba类反对称自旋轨道耦合控制。费米面分裂可以导致超导凝聚体中自旋单重态和自旋三重态的混合。自旋三重态的存在被认为是超导基态的各种不寻常特征的原因。在实验上，发现与BCS理论的预期有明显的偏差，一般来说，只有在那些系统中，除了失去反演对称性，电子之间存在强相关性。这类材料主要基于Ce、Yb或U。对于更大的一组没有实质性电子关联的材料，在绝大多数已知的例子中观察到了BCS类超导性。因此，非传统的超导性通常需要电子关联和非中心对称晶体结构的相互存在。(C)2015 Elsevier B.V.版权所有。
Superconductivity in absence of inversion symmetry of the crystal structure is basically controlled by a Rashba-like antisymmetric spin orbit coupling which splits the Fermi surface and removes the spin degeneracy of electrons. The Fermi surface splitting can originate a mixing of spin-singlet and spin-triplet states in the superconducting condensate. The presence of spin-triplet states is expected to be responsible for various uncommon features of the superconducting ground state. Experimentally, distinct deviations from the expectations of the BCS theory are found, in general, only in those systems where beside the missing of inversion symmetry strong correlations among electrons are present. Materials of this group are primarily based on Ce, Yb or U. For the much larger group of materials without substantial electronic correlations, BCS-like superconductivity was observed in the overwhelming number of known examples. Hence, unconventional superconductivity requires, in general, the mutual presence of electronic correlations and non-centrosymmetric crystal structures. (C) 2015 Elsevier B.V. All rights reserved.