This article from NIST discusses recent advances in the study of topological materials, particularly those with strong spin-orbit coupling and unique quantum properties. These materials, such as topological insulators and Weyl semimetals, exhibit exotic electronic behaviors that go beyond traditional symmetry-breaking phase transitions. Instead of relying on long-range order, these systems show topological order, which can lead to gapless boundary states with unique chiral properties. This has sparked significant interest in 4d, 5d, and 5f materials, where spin-orbit interactions are stronger and can give rise to new quantum phases like antiferromagnetic topological insulators and magnetic topological semimetals.
The research highlights the importance of these materials for future technologies, especially in spintronics and quantum computing. Examples include the discovery of Singular Angular MagnetoResistance (SAMR) in Weyl semimetals and the study of kagome lattices, which show complex magnetic structures and topological effects like the anomalous Hall effect. These findings are helping scientists better understand how to manipulate and control quantum states in materials, potentially leading to new devices that use these properties for information processing and storage. While many of these studies are still in the experimental or theoretical phase, they represent a growing effort to explore and classify new quantum phases of matter.
Source: https://www.nist.gov/ncnr/topological-systems-and-spin-orbit-coupling
Keywords: topological materials, spin-orbit interaction, topological order
