📝 SummarXiv

Abstract

Following recent intensive studies on altermagnets(ALM) characterized by non-relativistic even-parity spin splitting, realizing unconventional odd-parity magnetism has also attracted increasing interest. Here, using symmetry arguments based on spin-group analyses, we elucidate the sufficient condition, the breaking nonmagnetic time reversal symmetry(TRS), for the presence of odd-parity spin splitting in the collinear antiferromagnetic(AFM) systems, which is also proved as a standard odd-parity ALM. Then, we utilize the well-known Haldane-Hubbard model to identify the odd-parity spin splitting in the collinear AFM ground state where the nonmagnetic TRS is broken by sublattice currents coming from the Haldane hopping term. A comprehensive phase diagram involving the Haldane hopping strength and on-site coulomb repulsion is established to elucidate correlation-driven electronic phases. Moreover, we calculate the optical conductivity to illustrate the sublattice current induced odd-parity ALM, displaying a significant spin-degenerate peak in the vicinity of the single-particle energy gap. This work reveals the underlying mechanism for the realization of the unconventional odd-parity ALM in collinear AFM systems.