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arXiv · 2207.11376

Two-phonon scattering in non-polar semiconductors: a first-principles study of warm electron transport in Si

Benjamin Hatanpää·Alexander Y. Choi·Peishi S. Cheng·Austin J. Minnich
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Abstract

The ab-initio theory of charge transport in semiconductors typically employs the lowest-order perturbation theory in which electrons interact with one phonon (1ph). This theory is accepted to be adequate to explain the low-field mobility of non-polar semiconductors but has not been tested extensively beyond the low-field regime. Here, we report first-principles calculations of the electric field-dependence of the electron mobility of Si as described by the warm electron coefficient, $\beta$. Although the 1ph theory overestimates the low-field mobility by only around 20%, it overestimates $\beta$ by over a factor of two over a range of temperatures and crystallographic axes. We show that the discrepancy in $\beta$ is reconciled by inclusion of on-shell iterated 2-phonon (2ph) scattering processes, indicating that scattering from higher-order electron-phonon interactions is non-negligible even in non-polar semiconductors. Further, a ~20% underestimate of the low-field mobility with 2ph scattering suggests that non-trivial cancellations may occur in the perturbative expansion of the electron-phonon interaction.

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Benjamin Hatanpää, Alexander Y. Choi, Peishi S. Cheng, Austin J. Minnich. 2022-07-22. Two-phonon scattering in non-polar semiconductors: a first-principles study of warm electron transport in Si. https://doi.org/10.1103/physrevb.107.l041110

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