Chirality-driven mass enhancement in the kagome Hubbard model

TL;DR

This paper reveals how geometrical frustration in the kagome Hubbard model leads to mass enhancement due to emergent chirality degrees of freedom, evidenced by specific heat and spectral features.

Contribution

It introduces a novel mechanism of quasiparticle mass enhancement driven by chirality in a frustrated lattice, analyzed via cluster dynamical mean-field theory.

Findings

Mass enhancement linked to chirality entropy release

Hierarchy of energy scales among charge, spin, and chirality

Sharp peaks in specific heat and spectral functions

Abstract

We investigate the quasiparticle-mass enhancement in the Hubbard model on the frustrated kagome lattice by using a cluster extension of the dynamical mean-field theory. By analyzing the cluster density matrix, we find a hierarchy of energy scale among charge, spin, and chirality degrees of freedom. Large amount of entropy associated with the chirality is released at a much lower temperature than other energy scales for spin and charge fluctuations, leading to a sharp peak in the specific heat and the single-particle spectrum. The results manifest a generic mechanism of mass enhancement driven by an emergent composite degree of freedom under geometrical frustration.