Thermopower and Unconventional Nernst in the Predicted Type-II Weyl Semi-metal WTe${}_2$

Abstract

WTe${}_2$ is one of a series of recently discovered high mobility semimetals, some of whose properties are characteristic of topological Dirac or Weyl metals. One of its most interesting properties is the unsaturated giant magnetoresistance that it exhibits at low temperatures. An important question is the degree to which this property can be ascribed to a conventional semi-metallic model in which a highly compensated, high mobility metal exhibits large magnetoresistance. Here we show that the longitudinal thermopower (Seebeck effect) of semi-metallic WTe${}_2$ exfoliated flakes exhibits periodic sign changes about zero with increasing magnetic field that indicates distinct electron and hole Landau levels and nearly fully compensated electron and hole carrier densities. However, inconsistent with a conventional semi-metallic picture, we find a rapid enhancement of the Nernst effect at low temperatures that is nonlinear in magnetic field, which is consistent with Weyl points in proximity to the Fermi energy. Hence, we demonstrate the role played by the Weyl character of WTe${}_2$ in its transport properties.

16 pages, 3 figures

References in corpus (9)

• Titanic Magnetoresistance in WTe2
• Gate-Tunable Negative Longitudinal Magnetoresistance in the Predicted Type-II Weyl Semimetal WTe2
• Quantum oscillations, thermoelectric coefficients and the Fermi surface of semi-metallic WTe2
• Anisotropic Magnetotransport and Exotic Longitudinal Linear Magnetoresistance in WTe2 Crystals
• Anisotropic giant magnetoresistance in NbSb2
• Environmental Instability and Degradation of Single- and Few-Layer WTe2 Nanosheets in Ambient Conditions
• Magnetoresistance and Quantum Oscillations of an Electrostatically Tuned Semimetal-to-Metal Transition in Ultra-Thin WTe2
• The semiclassical theory of anomalous transport in type-II topological Weyl semimetals
• Correlation of Crystal Quality and Extreme Magnetoresistance of WTe${}_2$

Cited by in corpus (5)

• Topological quantum materials from the viewpoint of chemistry
• Direct evidence for charge compensation induced large magnetoresistance in thin WTe2
• Ultrafast photothermoelectric effect in Dirac semimetallic Cd3As2 revealed by terahertz emission
• Fermi surface and nested magnetic breakdown in WTe2
• Optical conductivity of the type-II Weyl semimetal WTe${}_2$ under pressure