Giant nonlinear conductivity in 2D electron gas from substrate-induced dipolar scattering

Abstract

Despite a surge of interest in the nonlinear transport in 2D materials, a fundamental puzzle remains: existing theoretical frameworks are unable to quantitatively account for the giant nonlinear conductivities ($\gtrsim 1\frac{\hat{I}¼\text{m}}{\hat{I}\text{c◯}\text{V}}$) recently reported in 2D van der Waals heterostructures. Here, we introduce a mechanism based on electron scattering from a substrate-induced dipole array linked to short-range impurities. We show that the strict kinematic constraints, inherent to 2D scattering, lead to a singular enhancement of the nonlinear response, fundamentally dictating a natural scale of $1\frac{\hat{I}¼\text{m}}{\hat{I}\text{c◯}\text{V}}$.

Updated version: added End Matter, additional references, updated text, fixed formatting. 4.5 pages, 2 figures