Altermagnetism and chiral spin liquids in a Lieb lattice Kitaev model

Altermagnets are characterized by crystal symmetry-compensated, momentum-dependent band splitting even in the absence of spin-orbit coupling (SOC). Building on recent developments combining key features of altermagnetism with frustrated quantum magnetism, we introduce a spin-orbital model with Kitaev-like, bond-dependent interactions on a Lieb lattice, which hosts gapless fractionalized fermionic excitations and localized Majorana fermions with zero-energy flat bands. Additional interactions that couple the spinless itinerant quasiparticles with local moments results in k-dependent splittings in their excitation spectrum. We detail the novel phases that emerge as a consequence of enmeshing altermagnetism and fractionalization in this quantum spin(-orbital) liquid (QSL).