Positive Magnetoresistance and Chiral Anomaly in Exfoliated Type-II Weyl Semimetal Td-WTe2

Rajdeep Adhikari, Soma Adhikari, Bogdan Faina, M. Terschanski, S. Bork, Claudia Leimhofer, M. Cinchetti, Alberta Bonanni

Research output: Contribution to journalArticlepeer-review

Abstract

Layered van der Waals semimetallic Td-WTe2, exhibiting intriguing properties which include non-saturating extreme positive magnetoresistance (MR) and tunable chiral anomaly, has emerged as a model topological type-II Weyl semimetal system. Here, ∼45 nm thick mechanically exfoliated flakes of Td-WTe2 are studied via atomic force microscopy, Raman spectroscopy, low-T/high-μ0H magnetotransport measurements and optical reflectivity. The contribution of anisotropy of the Fermi liquid state to the origin of the large positive transverse MR⊥ and the signature of chiral anomaly of the type-II Weyl Fermions are reported. The samples are found to be stable in air and no oxidation or degradation of the electronic properties is observed. A transverse MR⊥∼1200 % and an average carrier mobility of 5000 cm2V−1s−1 at T=5K for an applied perpendicular field μ0H⊥=7T are established. The system follows a Fermi liquid model for T≤50K and the anisotropy of the Fermi surface is concluded to be at the origin of the observed positive MR. Optical reflectivity measurements confirm the anisotropy of the electronic behaviour. The relative orientation of the crystal axes and of the applied electric and magnetic fields is proven to determine the observed chiral anomaly in the in-plane magnetotransport. The observed chiral anomaly in the WTe2 flakes is found to persist up to T=120K, a temperature at least four times higher than the ones reported to date.
Original languageEnglish
Article number2755
Pages (from-to)2755/1-18
Number of pages18
JournalNanomaterials
Volume11
DOIs
Publication statusPublished - 2021

Fields of science

  • 210006 Nanotechnology
  • 103 Physics, Astronomy
  • 103011 Semiconductor physics
  • 103018 Materials physics
  • 103009 Solid state physics
  • 103017 Magnetism

JKU Focus areas

  • Sustainable Development: Responsible Technologies and Management

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