Record magnetoresistance, enhanced superconductivity, and fermiology in WTe2

TL;DR

This study improves crystal quality of WTe2 using a new growth technique, revealing enhanced magnetoresistance, superconductivity, and detailed electronic properties, with potential applications in topological electronics.

Contribution

Refinement of a horizontal flux transport method for WTe2 yields crystals with less disorder, enabling new insights into its electronic and superconducting properties.

Findings

Achieved crystals with an order of magnitude less disorder.

Observed the largest magnetoresistance reported in a metal.

Detected quantum oscillations and a gated superconducting dome.

Abstract

The diverse electronic properties of transition metal chalcogenides can be very sensitive to crystal imperfections. A new crystal growth technique, known as horizontal flux transport, offers a route to improved crystal quality. By refining this technique and applying it to the topological semimetal WTe2, we achieved crystals with an order of magnitude less disorder as determined by electrical transport and scanning tunneling microscopy measurements. At low temperatures these crystals exhibit the largest magnetoresistance reported in a metal. Exfoliated monolayers show quantum oscillations for the first time in the electrostatically doped metallic states, enabling determination of band degeneracies and the valley splitting induced by an electric field. Moreover, they exhibit a gated superconducting dome with a greatly enhanced critical temperature approaching 1.8 K. This advance opens up new avenues for employing WTe2 in topological electronics and gated superconducting devices, and promises comparable breakthroughs with other chalcogenides.