Paramagnetic Effects of j-electron Superconductivity and Application to UTe2
Paramagnetic Effects of j-electron Superconductivity and Application to UTe2
复制标题
DOI：
10.7566/jpsj.90.034707
复制
发表时间：
2021-03-15
影响因子：
1.7
通讯作者：
Fujimoto, Satoshi
中科院分区：
文献类型：
--
作者：
Hiranuma, Kozo;Fujimoto, Satoshi
自旋三重态超导体UTe 2具有类伊辛磁各向异性，表明库珀对自旋平行于易磁化轴。然而，上临界场的难轴方向是远远大于易轴，这意味着强抑制的泡利depairing效应，即使在难轴方向。这一观察结果与最近的NMR测量结果相一致，NMR测量结果表明，在难磁化轴磁场的转变温度Tc以下，奈特位移略有下降。我们澄清，这些行为是自然理解的结果，多轨道f-电子带的总角动量j = 5/2。考虑到自旋-轨道耦合的正交结构，我们表明，对于难磁化轴磁场，自旋磁化率低于Tc和泡利depairing效应的下降被强烈抑制。
The putative spin-triplet superconductor UTe2 has an Ising-like magnetic anisotropy, indicating the Cooper pair spins parallel to the easy-axis. However, the upper critical field for the hard-axis direction is much larger than that for the easyaxis, implying the strong suppression of the Pauli depairing effect even for the hard-axis direction. This observation is consistent with the recent NMR measurements which show the tiny decrease of the Knight shift below the transition temperature T-c for hard-axis magnetic fields. We clarify that these behaviors are naturally understood as a result of multiorbital f-electron bands with total angular momentum j = 5/2. Taking into account spin-orbit couplings for an orthorhombic structure, we demonstrate that for hard-axis magnetic fields, the decrease of the spin susceptibility below T-c and the Pauli depairing effect are strongly suppressed.