A Correlated Route to Antiferromagnetic Spintronics

Abstract

Antiferromagnets are attractive for spintronics owing to their vanishing net magnetization and ultrafast spin dynamics, yet their spin-compensated electronic structure has long confined them to passive roles. Here we identify a symmetry selection rule that overcomes this limitation: in a collinear antiferromagnet, a spin-polarized dc charge current requires the simultaneous breaking of particle--hole symmetry and of the equivalence between the two magnetic sublattices, either one alone leaving the polarization identically zero. We demonstrate the rule in the doped antiferromagnetic Hubbard model within dynamical mean-field theory: doping and a uniform magnetic field each break one of the two symmetries, and electronic correlations convert the resulting hierarchy of spin-dependent scattering rates into a sizable, field-tunable polarization of the charge current. The polarization is largest deep in the ordered phase and reverses sign at an emergent compensation point, not dictated by symmetry, at which the dominant conducting spin species is interchanged. In correlated altermagnetic Hubbard models, the same two symmetries are broken structurally, by the sublattice-alternating hopping pattern: the field-driven mechanism identified here and the altermagnetic one are two realizations of a single selection rule. Electronic correlations thus emerge as an active ingredient for spintronics in structurally conventional collinear antiferromagnets.

Revised version. Expanded symmetry analysis and discussion of the connection with altermagnetic Hubbard models. Supplemental Material substantially extended, including the magnetic phase diagram, scattering-rate analysis, and a comparison with the paramagnetic solution