ISIS Facility, STFC Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Oxfordshire, United Kingdom.
Phys Rev Lett. 2012 Aug 31;109(9):097001. doi: 10.1103/PhysRevLett.109.097001. Epub 2012 Aug 27.
Muon spin rotation and relaxation experiments on the centrosymmetric intermetallic superconductor LaNiGa2 are reported. The appearance of spontaneous magnetic fields coincides with the onset of superconductivity, implying that the superconducting state breaks time reversal symmetry, similarly to noncentrosymmetric LaNiC2. Only four triplet states are compatible with this observation, all of which are nonunitary triplets. This suggests that LaNiGa2 is the centrosymmetric analogue of LaNiC2. We argue that these materials are representatives of a new family of paramagnetic nonunitary superconductors.
报道了对中心对称金属间化合物超导体 LaNiGa2 的 μ子自旋旋转和弛豫实验。自发磁场的出现与超导的开始相吻合，这意味着超导态破坏了时间反转对称性，类似于非中心对称的 LaNiC2。只有四个三重态与这一观察结果一致，它们都是非幺正三重态。这表明 LaNiGa2 是 LaNiC2 的中心对称类似物。我们认为这些材料是一类新的顺磁非幺正超导体的代表。
