Fermiology of a 1D heavy electron metal

TL;DR

This study uses Quantum Monte Carlo simulations to explore the electronic structure and temperature-dependent Fermi surface evolution in a one-dimensional heavy electron metal modeled by the Kondo lattice.

Contribution

It demonstrates reduced sign problem enabling low-temperature QMC simulations and reveals detailed Fermi surface changes with temperature in 1D heavy electron systems.

Findings

Low-temperature Green's function shows complex low-energy band structure.

Fermi surface includes both c and f-electrons at low temperature.

F-electrons drop out of the Fermi surface as temperature increases.

Abstract

We present a Quantum Monte Carlo (QMC) study of the 1D Kondo lattice at non-integer filling, i.e. a one-dimensional version of a heavy electron metal. For this special system the minus-sign problem turns out to be strongly reduced, which allows QMC simulations for temperatures as low as 1% of the conduction electron bandwidth. The single particle Green's function shows and intricate network of low-energy bands at low temperature, with a Fermi surface volume that comprises both c and f-electrons. As temperature increases the system evolves through two distinct crossover temperatures into a very simple band structure with one free c-electron band and a disconnected upper and lower Hubbard band for f-electrons. The f-electrons thus `drop out' of the Fermi surface volume as temperature increases.