Graduate School of Engineering Science, Osaka University, Osaka 560-8531, Japan.
Phys Rev Lett. 2010 Jan 8;104(1):017002. doi: 10.1103/PhysRevLett.104.017002. Epub 2010 Jan 7.
We report 29Si NMR study on a single crystal of the heavy-fermion superconductor CeIrSi3 without an inversion symmetry along the c axis. The 29Si Knight-shift measurements under pressure have revealed that the spin susceptibility for the ab plane decreases slightly below T(c), whereas along the c axis it does not change at all. The result can be accounted for by the spin susceptibility in the superconducting state being dominated by the strong antisymmetric (Rashba-type) spin-orbit interaction that originates from the absence of an inversion center along the c axis and it being much larger than superconducting condensation energy. This is the first observation which exhibits an anisotropy of the spin susceptibility below T(c) in the noncentrosymmetric superconductor dominated by strong Rashba-type spin-orbit interaction.
我们报告了对沿 c 轴没有反演对称的重费米子超导体 CeIrSi3 单晶体的 29Si NMR 研究。在压力下进行的 29Si 奈特位移测量表明，在 T(c)以下 ab 平面的自旋磁化率略有下降，而沿 c 轴则根本没有变化。该结果可以用超导态中的自旋磁化率主要由源自 c 轴上没有反演中心的强不对称（Rashba 型）自旋轨道相互作用来解释，这种相互作用比超导凝聚能大得多。这是首次在由强 Rashba 型自旋轨道相互作用主导的非中心对称超导体中观察到 T(c)以下自旋磁化率的各向异性。
