Acoustic phonon scattering in Bi2Te3/Sb2Te3 superlattices

Yaguo Wang, Purdue University
Carl Liebig, Purdue University - Main Campus
Xianfan Xu, Birck Nanotechnology Center, School of Materials Engineering, Purdue University
Rama Venkatasubramanian, RTI Int

Date of this Version



DOI: 10.1063/1.3483767

This document has been peer-reviewed.



Ultrafast time-resolved measurements were conducted to investigate long-wavelength acoustic phonon scattering and velocity reduction in Bi2Te3/Sb2Te3 superlattices. We show that both these phenomena suppress heat transfer process, with the phonon scattering contributing more in differentiating the lattice thermal conductivities among films with different periods. Measurements of reduction in the acoustic phonon amplitudes support the decrease in the thermal conductivity for certain superlattice periods, which is not predicted by acoustic mismatch theory. This study is a direct measurement of coherent acoustic phonons in superlattices which is of significant interest to thermoelectrics.


Engineering | Nanoscience and Nanotechnology