Evolution of a Large Fermi Surface in the Kondo Lattice

TL;DR

This study uses advanced computational methods to analyze how the Fermi surface in the Kondo lattice evolves with temperature, revealing a transition from local-moment to heavy Fermi-liquid states.

Contribution

It provides a detailed quantitative analysis of the Fermi surface evolution in the Kondo lattice using continuous-time quantum Monte Carlo and dynamical mean-field theory.

Findings

Identification of a crossover to a heavy Fermi-liquid state

Observation of a discontinuity in momentum distribution at low temperatures

Spectral features similar to the Anderson lattice despite absence of charge degrees

Abstract

Single-particle spectrum of the Kondo lattice model is derived with use of the continuous-time quantum Monte Carlo method, combined with the dynamical mean-field theory. Crossover behavior is traced quantitatively either to a heavy Fermi-liquid state or to a magnetically ordered state from the local-moment state at high temperatures. The momentum distribution in the low-temperature limit acquires a discontinuity at the location that involves the local-spin degrees of freedom. Even without the charge degrees of freedom for local electrons, the excitation spectra exhibit hybridized bands similar to those in the Anderson lattice. Temperature dependence in the zero-energy component of the self-energy is crucial in forming the Fermi-liquid state with the large Fermi surface.