Theory of Angle Resolved Photoemission Spectroscopy of Altermagnetic Mott Insulators.

Altermagnetism has emerged as an unconventional form of collinear magnetism with spatial rotational symmetries, that give rise to strongly spin-split bands despite an underlying fully compensated antiferromagnetic order. Here, we develop a theory for the angle resolved photoemission spectroscopy response of altermagnetic Mott insulators. Crucially, the spectrum does not simply reflect the noninteracting band structure, but instead a magnetic polaron is formed at low energies, that can be interpreted as a spinon-holon bound state. We develop a spinon-holon parton theory and predict a renormalized bandwidth that we confirm by tensor network simulations. We analyze the characteristic spin-split spectrum and identify a spin-dependent spectral weight of the magnetic polaron, resulting from the altermagnetic symmetry. Our Letter paves the way for a systematic study of doping effects and correlation phenomena in altermagnetic Mott insulators.