Jul 07, 2022
Research: Quasi-symmetry-protected topology in a semi-metal
Comparison between a mirror symmetry and quasi-symmetry operation. A mirror symmetry operation consistently acts on the whole object. In contrast, the quasi-symmetry operation acts differently on different parts of the system.
Symmetry is known as a guiding tool for the search for various quantum materials including recently discovered topological materials. An international team of researchers has introduced an alternative guiding principle, "quasi-symmetry". While conventional symmetry acts uniformly on the whole object, quasi-symmetry acts selectively. It thus opens the ways towards unexpected topological properties beyond the usual space-group classifications and hence the discovery of new types of quantum materials. The concept was proven through precise quantum oscillation measurements in CoSi.
C. Guo, L. Hu, C. Putzke, J. Diaz, X. Huang, K. Manna, F.-R. Fan, C. Shekhar, Y. Sun, C. Felser, C. Liu, B. A. Bernevig, P. J. W. Moll,
Quasi-symmetry-protected topology in a semi-metal,
Nature Physics (2022) (arXiv)