# Decoupling Heat and Electrical Conduction in Bilayer Graphene Through Wrinkling‐Induced Phonon Hybridization

## TL;DR

Wrinkles in bilayer graphene cause thermal and electrical conductivity to behave oppositely, offering new ways to control energy flow in electronic devices.

## Contribution

A nearly zero-strain wrinkling strategy in bilayer graphene reveals decoupled thermal and electrical transport due to phonon hybridization.

## Key findings

- Thermal conductivity perpendicular to wrinkles is lower than parallel to wrinkles.
- Electrical resistance perpendicular to wrinkles is lower than parallel to wrinkles.
- Phonon mode hybridization explains the decoupling of thermal and electrical transport.

## Abstract

2D materials like graphene are renowned for their exceptional thermal and electrical properties, yet their performance can be significantly altered by structural irregularities such as wrinkles. While previous studies have reported modulation of thermal conductivity (κ) and electrical resistance (R) in wrinkled graphene, the results are often inconsistent or even contradictory, primarily due to challenges in experimentally disentangling geometric distortion from lattice strain. Here, a nearly zero‐strain wrinkling strategy is introduced for bilayer graphene (BLG) and uncover a strikingly inverse anisotropic relationship: thermal conductivity perpendicular to the wrinkles (κ
⊥) is lower than that parallel to the wrinkles (κ
∥), whereas electrical resistance exhibits the opposite trend, with R
⊥ lower than R
∥, highlighting the decoupling of thermal and electrical transport in wrinkled graphene. Atomistic simulations reveal that this behavior arises from phonon mode hybridization induced by out‐of‐plane geometric perturbations, which decelerates heat‐carrying phonon modes across the wrinkles and modifies electron–phonon scattering, thereby governing both the thermal conductivity and phonon‐limited electrical resistance. This work advances the understanding of energy carrier transport in wrinkled 2D materials and provides new insights into directionally modulating heat and charge flow in advanced electronic devices.

Measurements of wrinkled bilayer graphene reveal a strikingly inverse anisotropic relationship: thermal conductivity perpendicular to the wrinkles is lower than that parallel to the wrinkles, whereas electrical conductivity exhibits the opposite trend, highlighting the decoupling of thermal and electrical transport in wrinkled graphene. Atomistic simulations reveal that this behavior arises from phonon mode hybridization induced by out‐of‐plane geometric perturbations.