Bulla, Ralf and Glossop, Matthew T. and Logan, David E. and Pruschke, Thomas (2000) The soft-gap Anderson model: comparison of renormalization group and local moment approaches. JOURNAL OF PHYSICS-CONDENSED MATTER, 12 (23). pp. 4899-4921. ISSN 0953-8984
Full text not available from this repository.Abstract
The symmetric Anderson impurity model with a hybridization vanishing at the Fermi level, Delta(1) proportional to \omega\(r), is studied via the numerical renormalization group (NRG) at T = 0; and detailed comparison made with predictions arising from the local moment approach (LMA), a recently developed many-body theory which is found to provide a remarkably successful description of the problem. Results fur the 'normal' (r = 0) impurity model are obtained as a specific case, and likewise compared. Particular emphasis is given both to single-particle excitation dynamics, and to the transition between the strong-coupling (SC) and local moment (LM) phases of the model. Scaling characteristics and asymptotic behaviour of the SC/LM phase boundaries are considered. Single-particle spectra D(omega) are investigated in some detail, for the SC phase in particular. Here, in accordance with a recently established result, the modified spectral functions F(omega) proportional to \omega\(r) D(omega) are found to contain a generalized Kondo resonance that is ubiquitously pinned at the Fermi level; and which exhibits a characteristic low-energy Kondo scale, omega(K)(r), that narrows progressively upon approach to the SC --> LM transition, where it vanishes. Universal scaling of the spectra as the transition is approached thus results. The scaling spectrum characteristic of the normal Anderson model is recovered as a particular case, that exemplifies behaviour characteristic of the SC phase generally, and which is captured quantitatively by the LMA. In all cases the r-dependent scaling spectra are found to possess characteristic low-energy asymptotics, but to he dominated by generalized Doniach-Sunjic tails, in agreement with LMA predictions.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | DILUTE MAGNETIC-ALLOYS; GAPLESS FERMI SYSTEMS; LARGE-N EXPANSION; PERTURBATION-THEORY; STATIC PROPERTIES; DOUBLE OCCUPANCY; CE COMPOUNDS; IMPURITIES; PHOTOEMISSION; VALENCE; |
| Subjects: | 500 Science > 530 Physics |
| Divisions: | Physics > Institute of Theroretical Physics |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 05 Apr 2022 13:34 |
| Last Modified: | 05 Apr 2022 13:34 |
| URI: | https://pred.uni-regensburg.de/id/eprint/42408 |
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