Journal
NATURE
Volume 527, Issue 7579, Pages 495-498Publisher
NATURE RESEARCH
DOI: 10.1038/nature15768
Keywords
-
Categories
Funding
- Microsoft Research
- Swiss National Science Foundation through the National Competence Center in Research MARVEL
- European Research Council through ERC Advanced Grant SIMCOFE
- ARO MURI [W911NF-12-1-0461]
- NSF CAREER [DMR-0952428]
- NSF MRSEC [DMR-0819860]
- Packard Foundation
- Keck grant
- National Natural Science Foundation of China
- 973 program of China [2011CBA00108, 2013CB921700]
- Chinese Academy of Sciences [XDB07020100]
- [ONR-N00014-11-1-0635]
- Division Of Materials Research
- Direct For Mathematical & Physical Scien [0952428] Funding Source: National Science Foundation
Ask authors/readers for more resources
Fermions-elementary particles such as electrons-are classified as Dirac, Majorana or Weyl. Majorana and Weyl fermions had not been observed experimentally until the recent discovery of condensed matter systems such as topological superconductors and semimetals, in which they arise as low-energy excitations(1-6). Here we propose the existence of a previously overlooked type of Weyl fermion that emerges at the boundary between electron and hole pockets in a new phase of matter. This particle was missed by Weyl(7) because it breaks the stringent Lorentz symmetry in high-energy physics. Lorentz invariance, however, is not present in condensed matter physics, and by generalizing the Dirac equation, we find the new type of Weyl fermion. In particular, whereas Weyl semimetals-materials hosting Weyl fermions-were previously thought to have standard Weyl points with a point-like Fermi surface (which we refer to as type-I), we discover a type-II Weyl point, which is still a protected crossing, but appears at the contact of electron and hole pockets in type-II Weyl semimetals. We predict that WTe2 is an example of a topological semimetal hosting the new particle as a low-energy excitation around such a type-II Weyl point. The existence of type-II Weyl points in WTe2 means that many of its physical properties are very different to those of standard Weyl semimetals with point-like Fermi surfaces.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available