Order parameter for the multichannel Kondo model at quantum criticality

Abstract

A multichannel Kondo model, where two or more equivalent but independent channels of electrons compete to screen a spin-1/2 impurity, shows overcompensation of the impurity spin, leading to the non-Fermi-liquid behavior in various thermodynamic and transport properties. However, when the channel symmetry is broken, an impurity quantum phase transition can occur at zero temperature. Identification of an order parameter describing the impurity quantum phase transition is very difficult since it is beyond the conventional Landau-Ginzburg-Wilson theory. By employing the natural orbitals renormalization group method, we study both two-channel and threechannel Kondo models, from the perspective of spin correlation between the impurity and electrons in electronic channels. Here we demonstrate that by introducing the spin-correlation ratio as an order parameter we can characterize impurity quantum phase transitions driven by channel asymmetry. In particular, the universal critical exponents $\beta$ of the spin-correlation ratio and $\nu$ of the correlation length are explicitly determined by finite-sizescaling analysis, namely, $\beta =0.10(1),\nu =2.0(1)$, and $\beta =0.10(1),\nu =2.5(1)$ for the two-channel and three-channel Kondo models, respectively.

7 pages, 7 figures

References in corpus (8)

• The numerical renormalization group method for quantum impurity systems
• Observation of the two-channel Kondo effect
• An order parameter for impurity systems at quantum criticality
• Scaling of tripartite entanglement at impurity quantum phase transitions
• Natural Orbitals Renormalization Group Approach to the Two-Impurity Kondo Critical Point
• Two-channel Kondo physics due to As vacancies in the layered compound ZrAs1.58Se0.39
• Strong vs. Weak Coupling Duality and Coupling Dependence of the Kondo Temperature in the Two-Channel Kondo Model
• An Anderson impurity interacting with the helical edge states in a quantum spin Hall insulator

Cited by in corpus (1)

• Magnetic correlation between two local spins in a quantum spin Hall insulator