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arXiv · 1001.2999

Effect of Spin-Orbit Interaction in Spin-Triplet Superconductor: Structure of ${\bf d}$-vector and Anomalous $^{17}$O-NQR Relaxation in Sr$_2$RuO$_4$

K. Miyake
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Abstract

Supposing the spin-triplet superconducting state of Sr$_2$RuO$_4$, the spin-orbit (SO) coupling associated with relative motion in Cooper pairs is calculated by extending the method for the dipole-dipole coupling given by Leggett in the superfluid $^{3}$He. It is shown that the SO coupling works only in the equal-spin pairing (ESP) state to make the pair angular momentum $\hbar{\vec L}$ and the pair spin angular momentum ${\rm i}{\vec d}\times{\vec d}^{*}$ parallel with each other. The SO coupling gives rise to the internal Josephson effect in a chiral ESP state as in superfluid A-phase of $^3$He with a help of an additional anisotropy arising from SO coupling of atomic origin which works to direct the {\bf d}-vector into $ab$-plane. This resolves the problem of the anomalous relaxation of $^{17}$O-NQR and the structure of {\bf d}-vector in Sr$_2$RuO$_4$.

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K. Miyake. 2010-01-18. Effect of Spin-Orbit Interaction in Spin-Triplet Superconductor: Structure of ${\bf d}$-vector and Anomalous $^{17}$O-NQR Relaxation in Sr$_2$RuO$_4$. https://doi.org/10.1143/jpsj.79.024714

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