Spin and orbital effects of Cooper pairs coupled to a single magnetic impurity

Abstract

The Kondo effect strongly depends on spin and orbital degrees of freedom of unconventional superconductivity. We focus on the Kondo effect in the $p_x+i{p}_y$-wave and $d_{x^2-y^2}+i{d}_{xy}$-wave superconductors to compare the magnetic properties of the spin-triplet and spin-singlet Cooper pairs. The difference appears when both of the paired electrons couple to a local spin directly. For the $p_x+i{p}_y$-wave, the ground state is always a spin doublet for a $S_{\mathrm{imp}}=1/2$ local spin, and it is always a spin singlet for $S_{\mathrm{imp}}=1$. The latter is due to uniaxial spin anisotropy of the triplet Cooper pair. For the $d_{x^2-y^2}+i{d}_{xy}$-wave, the interchange of ground states occurs, which resembles a competition between the Kondo effect and the superconducting energy gap in s-wave superconductors. Thus the internal degrees of freedom of Cooper pairs give a variety to the Kondo effect.

7 pages, 6 figures, RevTex, to be published in Phys. Rev. B

References in corpus (1)

• Orbital effect of Cooper pairs on Kondo effect in unconventional superconductors

Cited by in corpus (5)

• The numerical renormalization group method for quantum impurity systems
• Magnetic anisotropy effects on quantum impurities in superconducting host
• Single Impurity Effects in Multiband Superconductors with Different Sign Order Parameters
• Kondo screening in unconventional superconductors: The role of anomalous propagators
• Anomaly in the heat capacity of Kondo superconductors