Matter with apparent and hidden spin physics

TL;DR

This paper explores the distinction between apparent and hidden spin effects in materials, classifying them based on symmetry and interactions, and discusses their tunability and implications for material discovery.

Contribution

It provides a real-materials-based classification of spin effects into four categories, including hidden effects, and offers a framework for their systematic discovery.

Findings

Classified spin effects into four categories based on symmetry and interactions.

Discussed electric tunability and switching of spin effects in antiferromagnets.

Extended the concept of hidden effects to include symmetry considerations at the atomistic level.

Abstract

Materials with interesting physical properties are often designed based on our understanding of the target physical effects. The physical properties can be either explicitly observed ("apparent") or concealed by the perceived symmetry ("hidden") but still exist. Both are enabled by specific symmetries and induced by certain physical interactions. Using the underlying approach of condensed matter theory of real materials (rather than schematic model Hamiltonians), we discuss apparent and hidden physics in real materials focusing on the properties of spin splitting and spin polarization. Depending on the enabling symmetries and underlying physical interactions, we classify spin effects into four categories with each having two subtypes; representative materials are pointed out. We then discuss the electric tunability and switch of apparent and hidden spin splitting and polarization in antiferromagnets. Finally, we extend "hidden effects" to views that are farsighted in the sense of resolving the correct atomistic and reciprocal symmetry and replaced by the incorrect higher symmetry. This framework could guide and enable systematic discovery of such intriguing effects.