Altermagnetism in Heavy Fermion Systems: Mean-Field study on Kondo Lattice

TL;DR

This paper predicts altermagnet-like phases in a Kondo lattice model with alternating next-nearest-neighbor hopping, revealing potential for spintronic applications and guiding experimental detection in heavy fermion materials.

Contribution

It introduces a microscopic model demonstrating altermagnetism in heavy fermion systems and identifies three distinct ground states using mean-field theory.

Findings

Identification of a d-wave altermagnet state

Coexistence of altermagnetism and Kondo screening

Presence of a Kondo insulator phase

Abstract

Recently, a novel collinear magnet, i.e. the altermagnet (AM), with spin-splitting energy band and zero net magnetization have attracted great interest due to its potential spintronic applications. Here, we demonstrate AM-like phases in a microscopic Kondo lattice (KL) model with an alternating next-nearest-neighbor-hopping (NNNH). Such alternating NNNH take nonmagnetic atoms, neglected in usual antiferromagnetism study, into account when encountering real-life candidate AM materials. With the framework of fermionic parton mean-field theory, we find three different ground-states for the half-filling KL: 1) a $d$-wave AM state; 2) a coexistent phase with both $d$-wave AM and intrinsic Kondo screening effect; 3) a Kondo insulator. The AM-like states are characterized by their spin-splitting quasiparticle bands, Fermi surface, spin-resolved distribution function and conductivity. It is suggested that the magnetic quantum oscillation, scanning tunneling microscopy and charge transport measurement can detect those AM-like phases. We hope the present work may be useful for exploring AM-like phases in $f$-electron compounds such as CeNiAsO and Ce$_{4}$X$_{3}$(X=As,Sb,Bi).