Electrically driven robust tuning of lattice thermal conductivity

TL;DR

This paper demonstrates that applying an external electric field to 2D materials like graphene, silicene, and germanene can monotonically decrease their thermal conductivity by increasing phonon scattering, offering a new approach for thermal management.

Contribution

It reveals the mechanism by which electric fields modulate thermal transport in 2D materials through internal electric field reconstruction and charge induction.

Findings

Thermal conductivity decreases monotonically with electric field.

Electric field increases phonon scattering rates.

Ultra-low thermal conductivity achieved under electric field.

Abstract

Two-dimensional (2D) materials represented by graphene stand out in future electrical industry and have been widely studied. As a commonly existing factor in electronic devices, the electric field has been extensively utilized to modulate the performance. However, how the electric field regulates thermal transport is rarely studied. Herein, we investigate the modulation of thermal transport properties by applying the external electric field ranging from 0 to 0.4 VA-1, with bilayer graphene, monolayer silicene, and germanene as study cases. The monotonic decreasing trend of thermal conductivity of all the three materials is revealed. The significant effect on the scattering rate is found to be responsible for the decreased thermal conductivity by electric field. Further evidences show that the reconstruction of internal electric field and the generation of induced charges lead to the increased scattering rate from strong phonon anharmonicity. Thus, the ultra-low thermal conductivity emerges with external electric field applied. Applying external electric field to regulate thermal conductivity enlightens the constructive idea for high-efficient thermal management.