Thermal boundary resistance predictions with non-equilibrium Green's function and molecular dynamics simulations

TL;DR

This paper evaluates the accuracy of the non-equilibrium Green's function method with B"uttiker probes in predicting thermal boundary resistance, comparing it with molecular dynamics simulations for Si/heavy-Si interfaces, highlighting its effectiveness and spectral insights.

Contribution

The study demonstrates that NEGF with B"uttiker probes can reliably predict thermal boundary resistance and include anharmonic effects, aligning well with MD results and providing spectral details.

Findings

NEGF with B"uttiker probes agrees quantitatively with MD for wide mass ratios.

Unaltered Landauer approach yields artificial resistances at virtual interfaces.

Spectral analysis shows phonon mode scattering is crucial for thermal transport.

Abstract

The non-equilibrium Green's function (NEGF) method with B\"uttiker probe scattering self-energies is assessed by comparing its predictions for the thermal boundary resistance with molecular dynamics (MD) simulations. For simplicity, the interface of Si/heavy-Si is considered, where heavy-Si differs from Si only in the mass value. With B\"uttiker probe scattering parameters tuned against MD in homogeneous Si, the NEGF-predicted thermal boundary resistance quantitatively agrees with MD for wide mass ratios. Artificial resistances that the unaltered Landauer approach yield at virtual interfaces in homogeneous systems are absent in the present NEGF approach. Spectral information result from NEGF in its natural representation without further transformations. The spectral results show that the scattering between different phonon modes plays a crucial role in thermal transport across interfaces. B\"uttiker probes provide an efficient and reliable way to include anharmonicity in phonon related NEGF. NEGF including the B\"uttiker probes can reliably predict phonon transport across interfaces and at finite temperatures.