Electrically-driven robust tuning of lattice thermal conductivity

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Two-dimensional (2D) materials, such as graphene, are crucial for future electrical industry applications.
• Electric fields are widely used to modulate electronic device performance.
• The impact of electric fields on thermal transport in 2D materials remains under-explored.

Purpose of the Study:

• To investigate how external electric fields modulate thermal transport properties.
• To explore this modulation in bilayer graphene, monolayer silicene, and germanene.

Main Methods:

• Applied external electric fields ranging from 0 to 0.4 V Å⁻¹.
• Studied thermal conductivity modulation in selected 2D materials.
• Analyzed the underlying mechanisms of phonon scattering.

Main Results:

• Observed a monotonic decrease in thermal conductivity across all studied materials.
• Identified increased phonon scattering rate as the primary cause for reduced thermal conductivity.
• Found that electric field-induced changes in internal electric fields and charge generation enhance phonon anharmonicity and scattering.

Conclusions:

• External electric fields can effectively reduce thermal conductivity in 2D materials.
• This regulation mechanism, via enhanced phonon scattering, leads to ultralow thermal conductivity.
• The findings present a novel approach for thermal management in electronic systems.