Acoustic impedance and interface phonon scattering in Bi${}_2$Te${}_3$ and other semiconducting materials

Abstract

We present first principles calculations of the phonon dispersions of Bi2Te3 and discuss these in relation to the acoustic phonon interface scattering in ceramics. The phonon dispersions show agreement with what is known from neutron scattering for the optic modes. We find a difference between the generalized gradient approximation and local density results for the acoustic branches. This is a consequence of an artificial compression of the van der Waals bonded gaps in the Bi2Te3 structure when using the generalized gradient approximation. As a result local density approximation calculations provide a better description of the phonon dispersions in Bi${}_2$Te${}_3$. A key characteristic of the acoustic dispersions is the existence of a strong anisotropy in the velocities. We develop a model for interface scattering in ceramics with acoustic wave anisotropy and apply this to Bi2Te3 and compare with PbTe and diamond.

References in corpus (2)

• Microscopic mechanism of low thermal conductivity in lead-telluride
• Phonon spectrum and bonding properties of Bi${}_2$Se${}_3$: Role of strong spin-orbit interaction

Cited by in corpus (2)

• Nanoscale Surface Dynamics of Bi${}_2$Te${}_3$(111): Observation of a Prominent Surface Acoustic Wave and the Role of van der Waals Interactions
• Significant low lattice thermal conductivity and potential high thermoelectric figure of merit in Na${}_2$MgSn