Altermagnetism in heavy-fermion systems: Mean-field study on the Kondo lattice

Recently, a novel collinear magnet, i.e., the altermagnet (AM), with spin-splitting energy band and zero net magnetization has 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 takes 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: (i) a $d\text{\ensuremath{-}}\mathrm{wave}$ AM state; (ii) a coexistent phase with both $d\text{\ensuremath{-}}\mathrm{wave}$ AM and intrinsic Kondo screening effect; (iii) 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 $f\text{\ensuremath{-}}\mathrm{electron}$ compounds such as CeNiAsO and ${\mathrm{Ce}}_{4}{X}_{3}$ $(X=\mathrm{As}, \mathrm{Sb}, \mathrm{Bi})$.