Zero-field edge conductance limitation in 2D topological insulators

Determine what mechanism(s) limit the edge conductance at zero magnetic field in monolayer WTe2 and other two-dimensional topological insulators, despite single-particle backscattering being forbidden by time-reversal symmetry, to enable robust edge transport for applications.

Background

Monolayer WTe2 exhibits the expected characteristics of a two-dimensional topological insulator, including edge-localized conduction and suppression of backscattering protected by time-reversal symmetry. Nevertheless, experiments show that edge conduction diminishes with increasing edge length and freezes out below a few kelvin, indicating unknown limiting mechanisms.

Understanding and mitigating these limits is central to realizing practical devices that exploit helical edge modes for low-power electronics and quantum information technologies.