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Local-moment formation in gapless Fermi systems

Carlos Gonzalez-Buxton·Kevin Ingersent
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Abstract

Perturbative scaling is applied to the Anderson model for a localized level coupled to a Fermi system in which the density of states varies like $|E|^r$ near the Fermi energy ($E=0$). This model with $r=1$ or $2$ may describe magnetic impurities in unconventional superconductors and certain semiconductors. The pseudo-gap is found to suppress mixed valence in favor of local-moment behavior. However, the magnitude of the exchange coupling $J$ in the local-moment regime is reduced, thereby decreasing the parameter range within which the impurity becomes Kondo-screened at low temperatures.

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Carlos Gonzalez-Buxton, Kevin Ingersent. 1996-07-26. Local-moment formation in gapless Fermi systems. https://arxiv.org/abs/cond-mat/9607191

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