Unconventional Chiral Fermions and Large Topological Fermi Arcs in RhSi
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Open Access
- 17 November 2017
- journal article
- research article
- Published by American Physical Society (APS) in Physical Review Letters
- Vol. 119 (20), 206401
- https://doi.org/10.1103/physrevlett.119.206401
Abstract
The theoretical proposal of chiral fermions in topological semimetals has led to a significant effort towards their experimental realization. In particular, the Fermi surfaces of chiral semimetals carry quantized Chern numbers, making them an attractive platform for the observation of exotic transport and optical phenomena. While the simplest example of a chiral fermion in condensed matter is a conventional Weyl fermion, recent theoretical works have proposed a number of unconventional chiral fermions beyond the standard model which are protected by unique combinations of topology and crystalline symmetries. However, materials candidates for experimentally probing the transport and response signatures of these unconventional fermions have thus far remained elusive. In this Letter, we propose the RhSi family in space group No. 198 as the ideal platform for the experimental examination of unconventional chiral fermions. We find that RhSi is a filling-enforced semimetal that features near its Fermi surface a chiral double sixfold-degenerate spin-1 Weyl node at and a previously uncharacterized fourfold-degenerate chiral fermion at . Each unconventional fermion displays Chern number at the Fermi level. We also show that RhSi displays the largest possible momentum separation of compensative chiral fermions, the largest proposed topologically nontrivial energy window, and the longest possible Fermi arcs on its surface. We conclude by proposing signatures of an exotic bulk photogalvanic response in RhSi.
Keywords
Funding Information
- National Science Foundation (NSF-DMR-1507585, NSF-DMR-1006492)
- Division of Materials Research
- Gordon and Betty Moore Foundation (GBMF4547-HASAN)
- National Research Foundation Singapore (NRF-NRFF2013-03)
- U.S. Department of Energy (DE-FG02-07ER46352, DE-AC02-05CH11231)
- Office of Science
- Basic Energy Sciences
- Ministry of Science and Technology, Taiwan (MOST105-2112-M-110-014-MY3)
- National Cheng Kung University
- National Center for Theoretical Sciences
This publication has 51 references indexed in Scilit:
- Discovery of Weyl Fermion Semimetals and Topological Fermi Arc StatesAnnual Review of Condensed Matter Physics, 2017
- Beyond Dirac and Weyl fermions: Unconventional quasiparticles in conventional crystalsScience, 2016
- Colloquium: Topological band theoryReviews of Modern Physics, 2016
- Topological insulators and superconductorsReviews of Modern Physics, 2011
- Topological semimetal and Fermi-arc surface states in the electronic structure of pyrochlore iridatesPhysical Review B, 2011
- Colloquium: Topological insulatorsReviews of Modern Physics, 2010
- Quantum Spin Hall Effect and Topological Phase Transition in HgTe Quantum WellsScience, 2006
- Quantum Spin Hall Effect in GraphenePhysical Review Letters, 2005
- Topological Order and the Quantum Spin Hall EffectPhysical Review Letters, 2005
- Elektron und Gravitation. IThe European Physical Journal A, 1929