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arXiv · 0902.4334

Anderson impurity in a semiconductor

Martin R. Galpin·David E. Logan
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Abstract

We consider an Anderson impurity model in which the locally correlated orbital is coupled to a host with a gapped density of states. Single-particle dynamics are studied, within a perturbative framework that includes both explicit second-order perturbation theory and self-consistent perturbation theory to all orders in the interaction. Away from particle-hole symmetry the system is shown to be a generalized Fermi liquid (GFL) in the sense of being perturbatively connectable to the non-interacting limit; and the exact Friedel sum rule for the GFL phase is obtained. We show by contrast that the particle-hole symmetric point of the model is not perturbatively connected to the non-interacting limit, and as such is a non-Fermi liquid for all non-zero gaps. Our conclusions are in agreement with NRG studies of the problem.

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Martin R. Galpin, David E. Logan. 2009-02-25. Anderson impurity in a semiconductor. https://doi.org/10.1103/physrevb.77.195108

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