Non-Fermi liquid, unscreened scalar chirality and parafermions in a frustrated tetrahedron Anderson model

TL;DR

This paper explores a four-impurity Anderson model on a tetrahedron, revealing a novel fixed point with unscreened scalar chirality, emergent parafermions, and singular Fermi liquid behavior, expanding understanding of non-Fermi liquid states.

Contribution

It introduces a new fixed point in a tetrahedral Anderson model with scalar chirality and parafermions, highlighting a novel non-Fermi liquid phase and critical point.

Findings

Discovery of a novel fixed point with scalar chirality

Emergence of parafermions in the excitation spectrum

Diverging quasiparticle mass indicating singular Fermi liquid behavior

Abstract

We investigate a four-impurity Anderson model where localized orbitals are located at vertices of a regular tetrahedron and find a novel fixed point in addition to the ordinary Fermi liquid phase. That is characterized by unscreened scalar chirality of a tetrahedron. In this phase, parafermions emerges in the excitation spectrum and quasiparticle mass diverges as 1/|T log^3 T| at low temperatures (T). The diverging effective mass is a manifestation of singular Fermi liquid states as in the underscreened Kondo problem. Between the two phases, our Monte Carlo results show the existence of a non Fermi liquid critical point where the Kondo effects and the intersite antiferromagnetic interactions are valanced. Singular behaviors are prominent in the dynamics and we find that the frequency (omega) dependence of the self-energy (Sigma) is the marginal Fermi liquid like, -Im Sigma \sim |omega|.