B\"uttiker probes for dissipative phonon quantum transport in semiconductor nanostructures

TL;DR

This paper extends the B"uttiker probe method to phonon NEGF for semiconductor nanostructures, enabling efficient modeling of both coherent and incoherent phonon transport with realistic conductance predictions.

Contribution

It introduces a computationally efficient B"uttiker probe approach for phonon NEGF, accurately reproducing experimental conductances and capturing inelastic scattering effects.

Findings

B"uttiker probe parameters match experimental conductances of Si and Ge from 10K to 1000K.

Interface relaxation significantly affects heat conductance in SiGe heterojunctions.

Inelastic scattering is crucial for accurate phonon distribution modeling.

Abstract

Theoretical prediction of phonon transport in modern semiconductor nanodevices requires atomic resolution of device features and quantum transport models covering coherent and incoherent effects. The nonequilibrium Green's function method (NEGF) is known to serve this purpose very well, but is numerically very expensive. This work extends the very efficient B\"uttiker probe concept to phonon NEGF and discusses all implications of this method. B\"uttiker probe parameters are presented that reproduce within NEGF experimental phonon conductances of Si and Ge between 10K and 1000K. Results of this method in SiGe heterojunctions illustrate the impact of interface relaxation on the device heat conductance and the importance of inelastic scattering for the phonon distribution.