Regular and singular Fermi-liquid fixed points in quantum impurity models

Pankaj Mehta, Natan Andrei, P. Coleman, L. Borda, Gergely Zarand

Research output: Contribution to journalArticle

63 Citations (Scopus)

Abstract

We show that the traditional classification of quantum inpurity models based on thermodynamics is insufficient to probe the nature of their low-energy dynamics. We propose an analysis based on scattering theory, dividing Fermi liquids into regular Fermi liquids and singular Fermi liquids. In both cases electrons at the Fermi energy scatter elastically off the impurity, but in the case of regular Fermi liquids the scattering has analytical properties in the vicinity of the Fermi energy, while for singular Fermi liquids it does not, resulting in a breakdown of Nozières' Fermi-liquid picture and singular thermodynamic behavior. Using the Bethe ansatz and numerical renormalization group, we show that the ordinary Kondo model is a regular Fermi liquid whereas the underscreened Kondo model is a a singular Fermi liquid. Conventional regular Fermi liquid behavior is reestablished in an external magnetic field H, but with a density of states which diverges as 1 H. Our results may be relevant for the recently observed field-tuned quantum criticality in heavy electron materials.

Original languageEnglish
Article number014430
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume72
Issue number1
DOIs
Publication statusPublished - Oct 27 2005

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

Fingerprint Dive into the research topics of 'Regular and singular Fermi-liquid fixed points in quantum impurity models'. Together they form a unique fingerprint.

  • Cite this