Positive Magnetoresistance and Chiral Anomaly in Exfoliated Type-II Weyl Semimetal T(d)-WTe(2)

Layered van der Waals semimetallic [Formula: see text]-WTe [Formula: see text] , 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 [Formula: see text]-WTe [Formula: see text] are studied via atomic force microscopy, Raman spectroscopy, low-T/high- [Formula: see text] magnetotransport measurements and optical reflectivity. The contribution of anisotropy of the Fermi liquid state to the origin of the large positive transverse [Formula: see text] 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 [Formula: see text] ∼1200 % and an average carrier mobility of 5000 cm [Formula: see text] V [Formula: see text] s [Formula: see text] at [Formula: see text] for an applied perpendicular field [Formula: see text] are established. The system follows a Fermi liquid model for [Formula: see text] 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 WTe [Formula: see text] flakes is found to persist up to [Formula: see text] , a temperature at least four times higher than the ones reported to date.