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Evidence for topological type-II Weyl semimetal WTe₂.

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 WTe₂ 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 WTe₂ is a type-II Weyl semimetal by observing two unique transport properties simultaneously in one WTe₂ nanoribbon. The negative magnetoresistance induced by a chiral anomaly is quite anisotropic in WTe₂ 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 WTe₂ nanoribbon.

SUBMITTER: Li P

PROVIDER: S-EPMC5732285 | biostudies-literature | 2017 Dec

REPOSITORIES: biostudies-literature

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Evidence for topological type-II Weyl semimetal WTe2.

Li Peng P Wen Yan Y He Xin X Zhang Qiang Q Xia Chuan C Yu Zhi-Ming ZM Yang Shengyuan A SA Zhu Zhiyong Z Alshareef Husam N HN Zhang Xi-Xiang XX

Nature communications 20171215 1

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 WTe2 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 WTe2 is ...[more]

PMID: 29247186

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