Ground state properties of a Zeeman-split heavy metal

TL;DR

This paper investigates how a Zeeman field influences the ground state of heavy fermion metals by analyzing changes in Fermi surfaces, effective mass, and optical conductivity, providing theoretical insights relevant to experimental spectroscopy.

Contribution

It introduces a hybridization mean field theory approach to quantify the effects of Zeeman splitting and Kondo suppression on heavy fermion ground states.

Findings

Effective mass decreases with increasing Zeeman field.

Derived optical conductivity expression applicable to infrared spectroscopy.

Fermi surface splitting leads to distinct spin-dependent band structures.

Abstract

A Zeeman field affects the metallic heavy fermion ground state in two ways: (i) it splits the spin-degerenate conduction sea, leaving spin up and spin down Fermi surfaces with different band curvature; (ii) it competes with the Kondo effect and thus suppresses the mass enhancement. Taking these two effects into account, we compute the quasiparticle effective mass as a function of applied field strength within hybridization mean field theory. We also derive an expression for the optical conductivity, which is relevant to infrared spectroscopy measurements.