Cheng, Mengxing, Chowdhury, Tathagata ORCID: 0000-0002-0108-9719, Mohammed, Aaron and Ingersent, Kevin (2017). Phase boundaries of power-law Anderson and Kondo models: A poor man's scaling study. Phys. Rev. B, 96 (4). COLLEGE PK: AMER PHYSICAL SOC. ISSN 2469-9969

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Abstract

We use the poor man's scaling approach to study the phase boundaries of a pair of quantum impurity models featuring a power-law density of states rho(epsilon) proportional to | epsilon| (r), either vanishing (for r > 0) or diverging (for r < 0) at the Fermi energy epsilon = 0, that gives rise to quantum phase transitions between local-moment and Kondo-screened phases. For the Anderson model with a pseudogap (i.e., r > 0), we find the phase boundary for (a) 0 < r < 1/2, a range over which the model exhibits interacting quantum critical points both at and away from particle-hole (p-h) symmetry, and (b) r > 1, where the phases are separated by first-order quantum phase transitions that are accessible only for broken p-h symmetry. For the p-h-symmetric Kondo model with easy-axis or easy-plane anisotropy of the impurity-band spin exchange, the phase boundary and scaling trajectories are obtained for both r > 0 and r < 0. Throughout the regime of weak-to-moderate impurity-band coupling in which poor man's scaling is expected to be valid, the approach predicts phase boundaries in excellent qualitative and good quantitative agreement with the nonperturbative numerical renormalization group, while also establishing the functional relations between model parameters along these boundaries.

Item Type: Journal Article
Creators:
CreatorsEmailORCIDORCID Put Code
Cheng, MengxingUNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Chowdhury, TathagataUNSPECIFIEDorcid.org/0000-0002-0108-9719UNSPECIFIED
Mohammed, AaronUNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Ingersent, KevinUNSPECIFIEDUNSPECIFIEDUNSPECIFIED
URN: urn:nbn:de:hbz:38-225122
DOI: 10.1103/PhysRevB.96.045103
Journal or Publication Title: Phys. Rev. B
Volume: 96
Number: 4
Date: 2017
Publisher: AMER PHYSICAL SOC
Place of Publication: COLLEGE PK
ISSN: 2469-9969
Language: English
Faculty: Unspecified
Divisions: Unspecified
Subjects: no entry
Uncontrolled Keywords:
KeywordsLanguage
GAPLESS FERMI SYSTEMS; RENORMALIZATION-GROUP APPROACH; LOCAL MOMENT APPROACH; MAGNETIC-IMPURITIES; SUPERCONDUCTORS; TRANSITION; PSEUDOGAP; METALSMultiple languages
Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed MatterMultiple languages
Refereed: Yes
URI: http://kups.ub.uni-koeln.de/id/eprint/22512

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