Parity and time-reversal invariant Ising spin ordering

TL;DR

This paper introduces a new class of antiferromagnets with symmetric Ising spin order that enables novel non-relativistic spin phenomena, including spin conductivities and spin-splittings, with potential material applications.

Contribution

The study reveals a new class of coplanar antiferromagnets with P and T symmetric Ising order that produce unconventional spin responses, expanding the understanding of spintronic materials.

Findings

Identification of 16 candidate materials with the proposed properties.

Demonstration of non-relativistic spin conductivities in these antiferromagnets.

Prediction of spin-splittings induced by light and electric fields.

Abstract

The interplay of antiferromagnetic order, momentum-dependent Bloch spin-splitting, time-reversal (T), and parity (P) symmetries in non-relativistic systems has emerged as a central theme for spintronics. Two well-known examples are P-preserving and T-violating altermagnets and P-violating and T-preserving odd-parity magnets. These both exhibit an Ising, or uniaxial, Bloch spin-splitting. Here we introduce a new class of coplanar AFMs that generate a P and T symmetric, translation-invariant Ising spin order in real space. Naively, such AFMs are not expected to exhibit unusual phenomena. Here we show that the spin-rotational symmetry breaking generated by these AFMs allows: pure non-relativistic longitudinal (or transverse) spin-conductivities, the generation of non-relativistic altermagnetic spin-splittings through circularly polarized light, and the generation of non-relativistic odd-parity spin-splittings through parity symmetry breaking, by, for example, applied electric fields. We identify 16 candidate materials in the Magndata database for which our theory applies and provide effective microscopic models and DFT-based results that highlight the large emergent responses.