A Correlated Route to Antiferromagnetic Spintronics

Abstract

Antiferromagnets offer an attractive platform for spintronics due to their absence of net magnetization and ultrafast spin dynamics, yet their intrinsically spin-compensated electronic structure has traditionally limited their active role in spin transport. Here we identify a minimal, correlation-driven route to spin-polarized charge transport in collinear antiferromagnets. Using the doped antiferromagnetic Hubbard model within dynamical mean-field theory, we show that electronic correlations generate strong spin-dependent scattering upon doping away from half filling, while a uniform magnetic field lifts the residual symmetries that enforce spin-degenerate transport. Only the combined breaking of particle--hole symmetry by doping and of the antiferromagnetic sublattice equivalence by the applied magnetic field converts these dynamical asymmetries into a finite spin polarization of the charge current. Our results establish electronic correlations as an active ingredient for antiferromagnetic spintronics and reveal a correlated analogue of the symmetry-breaking mechanism underlying altermagnetic spin-polarized transport in structurally conventional, collinear antiferromagnets.

Figures (2)

• Figure 1: Sublattice- and spin-resolved local spectral functions $A^{\alpha\alpha}_{\sigma}(\omega)$ for the four relevant regimes. From left to right: half filling without magnetic field, doped system at zero field, half-filled system under a magnetic field, and doped system under a magnetic field. Only the combined action of doping and magnetic field fully removes the spectral symmetries enforcing spin-degenerate transport. Unless otherwise stated, the plots correspond to $h=0.07$ and $\delta=0.028$.
• Figure 2: Spin-resolved dc conductivity (left) and current polarization, $P=(\sigma_{\uparrow}-\sigma_{\downarrow})/(\sigma_{\uparrow}+\sigma_{\downarrow})$ (right), as a function of doping within the antiferromagnetic regime, $\delta<\delta_c$, with $\delta_c$ the critical doping above which Néel order collapses. The left panel shows the spin-resolved dc conductivities for zero field ($h=0$) and for a representative finite field ($h=0.03$). The right panel shows the corresponding current polarization for several magnetic fields, highlighting the tunability of $P$ with doping and field strength. A finite spin polarization of the charge current emerges only when both particle--hole symmetry and antiferromagnetic sublattice equivalence are simultaneously broken.