Pseudogap Behavior in the Local Spinon Spectrum of Power-Law Diverging Multichannel Kondo Model

TL;DR

This paper investigates how higher-order van Hove singularities influence the multichannel Kondo model, revealing a crossover from non-Fermi liquid to pseudogap behavior in the local impurity spectrum, with potential implications for strongly correlated materials.

Contribution

It introduces a detailed analysis of the multichannel Kondo model near higher-order van Hove singularities, showing a tunable crossover to pseudogap behavior based on the singularity exponent and channel-spin ratio.

Findings

Identifies conditions for crossover from non-Fermi liquid to pseudogap behavior.

Determines the critical parameters for the pseudogap phase emergence.

Provides insights into the interplay between van Hove singularities and Kondo physics.

Abstract

Motivated by the emergence of higher-order van Hove singularities (VHS) with power-law divergent density of states (DOS) ($\rho_c(\omega)=\rho_0/|\omega|^{r}$, $0<r<1$) in materials, we investigate a multichannel Kondo model involving conduction electrons near the higher-order van Hove filling. This model considers $M$ channel and $N$ spin degrees of freedom. Employing a renormalization group analysis and dynamical large-$N$ approach, our results reveal a crossover from a non-Fermi liquid to pseudogap behavior in the spectral properties of the local impurity at the overscreened fixed point. We precisely determine the conditions under which the crossover occurs, either by tuning the exponent $r$ or the ratio $\kappa=M/N$ to a critical value. This pseudogap phase of spinon exhibits distinct physical properties that could have an impact on the properties of real systems. The results of this study provide novel insights into the non-Fermi liquid and pseudogap behaviors observed in strongly correlated systems and offer a playground to study the interplay between higher-order van Hove singularities and multichannel Kondo physics.