Quantum phase transition in a gapped Anderson model: A numerical renormalization group study

Abstract

We use the numerical renormalization group method to investigate the spectral properties of a single-impurity Anderson model with a gap δ across the Fermi level in the conduction-electron spectrum. For any finite δ > 0, at half filling the ground state of the system is always a doublet. Away from half filling a quantum phase transition (QPT) occurs as function of the gap value δ, and the system evolves from the strong-coupling (SC) Kondo-type state, corresponding to δ <δ_C toward a localized moment (LM) regime for δ > δ_C. The opening of the gap leads to the formation of one (two) bound states when the system is in the SC (LM) regime. The evolution across the QPT of their positions and the corresponding weights together with the dynamic properties of the model are investigated.

6 pages, 6 eps figures

References in corpus (8)

• The numerical renormalization group method for quantum impurity systems
• Quantum phase transition in a two-channel-Kondo quantum dot device
• Anderson impurities in gapless hosts: comparison of renormalization group and local moment approaches
• Numerical renormalization group calculation of near-gap peaks in spectral functions of the Anderson model with superconducting leads
• Kondo effect in coupled quantum dots with RKKY interaction: Finite temperature and magnetic field effects
• Kondo Effect in Fermi Systems with a Gap: A Renormalization Group Study
• Anderson impurity in a semiconductor
• An Anderson Impurity in a Semiconductor

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• Rigorous Wilsonian Renormalization Group for impurity models with a spectral gap
• Unified theory of quantum phase transitions in quantum dots with gapped host bands
• Reentrant Kondo effect in a quantum impurity coupled to a metal-semiconductor hybrid contact
• Quantum phase transitions into Kondo states in bilayer graphene
• Kondo Phase Transitions of Magnetic Impurities in Carbon Nanotubes
• Tunneling spectroscopy of the spinon-Kondo effect in one-dimensional Mott insulators