Evidence for topological type-II Weyl semimetal WTe<sub>2</sub>.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 29247186.
- Also identified by DOI 10.1038/s41467-017-02237-1 and PMC identifier 5732285.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Recently, a type-II Weyl fermion was theoretically predicted to appear at the contact of electron and hole Fermi surface pockets. A distinguishing feature of the surfaces of type-II Weyl semimetals is the existence of topological surface states, so-called Fermi arcs. Although WTe<sub>2</sub> was the first material suggested as a type-II Weyl semimetal, the direct observation of its tilting Weyl cone and Fermi arc has not yet been successful. Here, we show strong evidence that WTe<sub>2</sub> is a type-II Weyl semimetal by observing two unique transport properties simultaneously in one WTe<sub>2</sub> nanoribbon. The negative magnetoresistance induced by a chiral anomaly is quite anisotropic in WTe<sub>2</sub> nanoribbons, which is present in b-axis ribbon, but is absent in a-axis ribbon. An extra-quantum oscillation, arising from a Weyl orbit formed by the Fermi arc and bulk Landau levels, displays a two dimensional feature and decays as the thickness increases in WTe<sub>2</sub> nanoribbon.