Strain engineering on the thermal conductivity and heat flux of thermoelectric Bi2Te3 nanofilm

Abstract

Using molecular dynamic calculations, we studied the strain effects on the thermal conductivity and local heat flux distribution in thermoelectric Bi2Te3 nanofilm. It is found that the thermal conductivity of Bi2Te3 nanofilm can be effectively tuned by strain. Remarkably, a 6% tensile strain is able to reduce the thermal conductivity by 50% while a 4% compressive strain is able to increase the thermal conductivity by 60%. Interestingly, the local heat flux in individual atomic layer responds quite differently to tensile and compressive strain: Tensile strain leads to a more uniform heat flux distribution while compressive strain leads to an opposite trend. Through analyzing the phonon vibrational spectrum, we reveal the underlying physical insights into the relationship among strain, thermal conductivity and heat flux distribution. The present work provides a possible route to effectively tune the thermal conductivity of thermoelectric Bi2Te3 nanofilm through strain engineering.