# Controlling Thermal Conductivity of Two-dimensional Materials via Externally Induced Phonon-Electron Interaction

## TL;DR

This paper investigates how external electrostatic gating can modulate phonon-electron interactions in 2D materials, significantly reducing their thermal conductivity and enabling potential thermal switching applications.

## Contribution

It introduces an ab initio approach and an analytical model to understand and control phonon-electron scattering in 2D materials, a previously unexplored area.

## Key findings

- Over 40% reduction in thermal conductivity in silicene with charge carrier concentration of 10^13 cm^-2
- Demonstrates feasibility of thermal conductivity control via electrostatic gating in 2D materials
- Provides guidelines for designing 2D materials with enhanced phonon-electron scattering

## Abstract

Phonon scattering by electrons, or "phonon-electron scattering", has been recognized as a significant scattering channel for phonons in materials with high electron concentration, such as thermoelectrics and nanoelectronics, even at room temperature. Despite the abundant previous studies of phonon-electron scattering in different types of three-dimensional (3D) bulk materials, its impact on the phonon transport, and thus the heat transfer properties, of two-dimensional (2D) materials has not been understood. In this work, we apply ab initio methods to calculate the phonon-electron scattering rates in two representative 2D materials, silicene and phosphorene, and examine the potential of controlling the thermal conductivity of these materials via externally induced phonon-electron scattering by electrostatic gating. We also develop an analytical model to explain the impact of reduced dimensionality and distinct electron and phonon dispersions in 2D on phonon-electron scattering processes. We find that over 40\% reduction of the lattice thermal conductivity can be achieved in silicene with an induced charge carrier concentration in the range of $10^{13}~cm^{-2}$, which is experimentally achievable. Our study not only generates new fundamental insights into phonon transport in 2D materials but also provides practical guidelines to search for 2D materials with strong phonon-electron scattering for potential thermal switching applications.