Title: Spin space group and collinear magnetic structure

Abstract:
Recent research has found that for magnetic materials with weak spin-orbit coupling(SOC), a new type of group  can be used to describe their symmetry: the spin space group(SSG). Starting from the magnetic groups, we briefly introduce the basic properties and construction of SSGs, as well as their rationale for describing a higher symmetry beyond MSGs.
SSGs have also begun to demonstrate their functionality in specific materials. Taking collinear magnetic materials as an easy example, we introduce how to further classify these materials using SSGs and perform symmetry analysis. A new terminology, "altermagnetism", has also been recently proposed. It describes a class of magnetic structures previously thought to belong to the antiferromagnetic class but possessing some properties not found in conventional antiferromagnets like AHE.

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