High Current Density and Low Thermal Conductivity of Atomically Thin Semimetallic WTe2

TL;DR

This study demonstrates that atomically thin WTe2 can sustain extremely high current densities while maintaining low thermal conductivity, highlighting its potential for stable, high-performance electronic applications.

Contribution

We developed a growth method for stable, atomically thin WTe2 and characterized its electrical and thermal properties, revealing its high current capacity and low thermal conductivity.

Findings

Ultra-thin WTe2 carries current densities up to 50 MA/cm2.

Encapsulated WTe2 remains stable and metallic in the thinnest form.

Thermal conductivity of WTe2 is approximately 3 W/m/K.

Abstract

Two-dimensional (2D) semimetals beyond graphene have been relatively unexplored in the atomically-thin limit. Here we introduce a facile growth mechanism for semimetallic WTe2 crystals, then fabricate few-layer test structures while carefully avoiding degradation from exposure to air. Low-field electrical measurements of 80 nm to 2 um long devices allow us to separate intrinsic and contact resistance, revealing metallic response in the thinnest encapsulated and stable WTe2 devices studied to date (3 to 20 layers thick). High-field electrical measurements and electro-thermal modeling demonstrate that ultra-thin WTe2 can carry remarkably high current density (approaching 50 MA/cm2, higher than most common interconnect metals) despite a very low thermal conductivity (of the order ~3 W/m/K). These results suggest several pathways for air-stable technological viability of this layered semimetal.