Abstract
Based on the nonequilibrium Green's function formalism, we show a numerically efficient method to treat inelastic scattering in multidimensional atomistic codes. Using a simple rescaling approach, we detail the calculations of the lowest-order approximation (LOA) [Y. Lee et al., Phys. Rev. B 93, 205411 (2016)] series to the usual, computationally intensive, self-consistent Born approximation (SCBA). This, combined with the analytic continuation technique of Padé approximants, is applied to an atomistic code based on a tight-binding model for electrons and holes, and a modified valence-force-field method for phonons. Currents in Si and Ge gate-all-around nanowire transistors are then computed considering the main crystallographic transport directions (, , ) for both -type and -type devices. Our results show that in most configurations, third-order LOA currents are enough to achieve a high agreement with SCBA results, while reducing the calculation time by about one order. In addition, we propose a criterion to determine the validity of such expansion techniques.
- Received 7 February 2017
- Revised 5 April 2017
DOI:https://doi.org/10.1103/PhysRevB.95.201412
©2017 American Physical Society