Higher angular momentum Kondo liquids

TL;DR

This paper investigates the theoretical possibility of Kondo liquids with d-wave internal angular momentum, revealing unique quasiparticle properties and potential quantum Hall phenomena in anisotropic correlated Fermi liquids.

Contribution

It introduces the concept of d-wave Kondo singlets, explores their energetic favorability, and studies their distinctive quasiparticle and topological properties.

Findings

Quasiparticle residue vanishes at isolated Fermi surface points

Large angle dependence of effective mass and quasiparticle residue

Potential for quantum Hall effects in Kondo insulators with complex angular momentum

Abstract

Conventional heavy Fermi liquid phases of Kondo lattices involve the formation of a "Kondo singlet" between the local moments and the conduction electrons. This Kondo singlet is usually taken to be in an internal s-wave angular momentum state. Here we explore the possibility of phases where the Kondo singlet has internal angular momentum that is d-wave. Such states are readily accessed in a slave boson mean field formulation, and are energetically favorable when the Kondo interaction is between a local moment and an electron at a nearest neighbor site. The properties of the d-wave Kondo liquid are studied. Effective mass and quasiparticle residue show large angle dependence on the Fermi surface. Remarkably in certain cases, the quasiparticle residue goes to zero at isolated points (in two dimensions) on the Fermi surface. The excitations at these points then include a free fractionalized spinon. We also point out the possibility of quantum Hall phenomena in two dimensional Kondo {\em insulators}, if the Kondo singlet has complex internal angular momentum. We suggest that such d-wave Kondo pairing may provide a useful route to thinking about correlated Fermi liquids with strong anisotropy along the Fermi surface.