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

TL;DR

This paper introduces a substrate-induced dipolar scattering mechanism that explains the giant nonlinear conductivity observed in 2D electron gases, highlighting a fundamental kinematic enhancement effect.

Contribution

It proposes a new theoretical framework based on substrate-induced dipolar scattering to account for giant nonlinear conductivities in 2D materials.

Findings

Identifies substrate-induced dipolar scattering as a key mechanism.

Shows that kinematic constraints lead to a singular enhancement.

Predicts a natural scale of nonlinear conductivity around 1 μm/ΩV.

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 ($\gtrsim 1 \frac{\mu \text{m}}{\Omega \text{V}}$) recently reported in 2D van der Waals heterostructures. Here, we introduce a mechanism based on electron scattering from a substrate-induced periodic dipole array. 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 $1 \frac{\mu \text{m}}{\Omega \text{V}}$.