The 2-Channel Kondo Model II: CFT Calculation of Non-Equilibrium Conductance through a Nanoconstriction containing 2-Channel Kondo Impurities

Abstract

Recent experiments by Ralph and Buhrman on zero-bias anomalies in quenched Cu nanoconstrictions (reviewed in the preceding paper, I), are in accord with the assumption that the interaction between electrons and nearly degenerate two-level systems in the constriction can be described, for sufficiently small voltages and temperatures ($V,T < \Tk$), by the 2-channel Kondo (2CK) model. Motivated by these experiments, we introduce a generalization of the 2CK model, which we call the nanoconstriction 2-channel Kondo model (NTKM), that takes into account the complications arising from the non-equilibrium electron distribution in the nanoconstriction. We calculate the conductance $G(V,T)$ of the constriction in the weakly non-equilibrium regime of $V,T \ll \Tk$ by combining concepts from Hershfield's $Y$-operator formulation of non-equilibrium problems and Affleck and Ludwig's exact conformal field theory (CFT) solution of the 2CK problem (CFT technicalities are discussed in a subsequent paper, III). Finally, we extract from the conductance a universal scaling curve $\Gamma (v)$ and compare it with experiment. Combining our results with those of Hettler, Kroha and Hershfield, we conclude that the NTKM achieves quantitative agreement with the experimental scaling data.

Final published version (minor revisions only), 41 pages RevTeX, 9 encapsulated postscript figures

References in corpus (4)

• Overscreened multi-channel SU(N) Kondo model : large-N solution and Conformal Field Theory
• Finite-Size Bosonization of 2-Channel Kondo Model: a Bridge between Numerical Renormalization Group and Conformal Field Theory
• The 2-Channel Kondo Model I: Review of Experimental Evidence for its Realization in Metal Nanoconstrictions
• Instability of the marginal commutative model of tunneling centers interacting with metallic environment: Role of the electron-hole symmetry breaking

Cited by in corpus (17)

• Observation of the two-channel Kondo effect
• Dephasing in Metals by Two-Level Systems in the 2-Channel-Kondo Regime
• Non-linear response of a Kondo system: Perturbation approach to the time dependent Anderson impurity model
• Charge transport in graphene-based mesoscopic realizations of Sachdev-Ye-Kitaev models
• Quantum Criticality out of Equilibrium: Steady State in a Magnetic Single-Electron Transistor
• Exact nonequilibrium transport in the topological Kondo effect
• Dynamical conductance in the two-channel Kondo regime of a double dot system
• Transport properties and point contact spectra of Ni_xNb_{1-x} metallic glasses
• Nonequilibrium Kondo problem with spin-dependent chemical potentials: Exact results
• Slow two-level systems in point contacts
• Kondo effect in mesoscopic systems
• Kondo Effect in Systems with Spin Disorder
• Nonequilibrium Quantum Critical Steady State: Transport Through a Dissipative Resonant Level
• Extended strange metal regime from superconducting puddles
• Two channel orbital Kondo effect in quantum dot with SO(n) symmetry
• Conductance of a Dissipative Quantum Dot: Nonequilibrium Crossover Near a Non-Fermi-Liquid Quantum Critical Point
• Unraveling screening mechanisms in Kondo impurities using an NRG-MPS-based method