Triple Point Topological Metals

Topologically protected fermionic quasiparticles appear in metals, where band degeneracies occur at the Fermi level, dictated by the band structure topology. While in some metals these quasiparticles are direct analogues of elementary fermionic particles of the relativistic quantum field theory, oth...

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Bibliographic Details
Main Authors: Zhu, Ziming, Winkler, Georg W., Wu, QuanSheng, Li, Ju, Soluyanov, Alexey A.
Other Authors: Massachusetts Institute of Technology. Department of Materials Science and Engineering
Format: Article
Language:English
Published: American Physical Society 2017
Online Access:http://hdl.handle.net/1721.1/110386
https://orcid.org/0000-0002-7841-8058
Description
Summary:Topologically protected fermionic quasiparticles appear in metals, where band degeneracies occur at the Fermi level, dictated by the band structure topology. While in some metals these quasiparticles are direct analogues of elementary fermionic particles of the relativistic quantum field theory, other metals can have symmetries that give rise to quasiparticles, fundamentally different from those known in high-energy physics. Here, we report on a new type of topological quasiparticles—triple point fermions—realized in metals with symmorphic crystal structure, which host crossings of three bands in the vicinity of the Fermi level protected by point group symmetries. We find two topologically different types of triple point fermions, both distinct from any other topological quasiparticles reported to date. We provide examples of existing materials that host triple point fermions of both types and discuss a variety of physical phenomena associated with these quasiparticles, such as the occurrence of topological surface Fermi arcs, transport anomalies, and topological Lifshitz transitions.