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Controllable Interface Junction, In-Plane Heterostructures Capable of Mechanically Mediating On-Demand Asymmetry of Thermal Transports

Gao, Yuan, Xu, Baoxing
ACS applied materials & interfaces 2017 v.9 no.39 pp. 34506-34517
asymmetry, deformation, electronics, heat, manufacturing, models, molecular dynamics, nitrides, tensile strength
Designing structures with thermal rectification performance that can be regulated by or adapted to mechanical deformation is in great demand in wearable electronics. Herein, using nonequilibrium molecular dynamics simulation, we present an in-plane graphene-boron nitride heterostructure with a controlled interface junction and demonstrate that its thermal transport ability is asymmetric when reversing the direction of heat flow. Such thermal rectification performance can be further regulated by applying an external tensile loading due to the mitigation of stress concentration, phonon resonance, and phonon localization. The analyses on heat flow distribution, vibrational spectra, and phonon participation suggest that the out-of-plane phonon modes dominate thermal rectification at a small tensile strain, while the mechanical stress plays a dominant role in regulation at a large tensile strain due to the weakened localization of out-of-plane phonon modes. The effect of tensile loading on the thermal rectification is demonstrated by selective interface junction-enabled heterostructures, and the results indicate that both asymmetry and direction of thermal transport can be controlled by introducing defects to the interface junction and/or applying mechanical tensile strain. These findings and models are expected to provide an immediate guidance for designing and manufacturing 2D material-based devices with mechanically tunable thermal management capabilities.