Doping, Frustration, and Fractionalization in SU(4) Quantum Magnets

Doping Mott insulators with strong interactions can lead to unexpected orders of local magnetic moments, akin to Nagaoka ferromagnetism. We investigate the fate of hole doping a SU(4) quantum magnet on frustrated triangular lattices. We find that the kinetic frustration in a t-J model with strong interactions can be relieved by fractionalizing the doped holes into fermionic spinons and bosonic holons. The holons minimize their kinetic energy when the spinons form a spinon Fermi surface. We establish this analytically in the large-N limit and simulate the SU(4) case numerically with matrix product state and variational Monte Carlo methods. We discuss possible experimental realizations in moiré heterostructures and dynamical probes to search for the fractionalized quasiparticles.