Relaxation time approximations in PAOFLOW 2.0

TL;DR

This paper introduces advanced relaxation time approximation models in PAOFLOW 2.0 for more accurate Boltzmann transport calculations, including a self-consistent fitting method to experimental data for extracting scattering rates.

Contribution

It implements energy and temperature dependent relaxation time models in PAOFLOW 2.0 and introduces a self-consistent fitting approach for scattering rates based on experimental conductivity.

Findings

Enhanced accuracy in transport property calculations.

Successful application to materials like GaAs, Si, Mg3Sb2, and CoSb3.

Flexible tool for extracting scattering rates from experimental data.

Abstract

Regardless of its success, the constant relaxation time approximation has limited validity. Temperature and energy dependent effects are important to match experimental trends even in simple situations. We present the implementation of relaxation time approximation models in the calculation of Boltzmann transport in PAOFLOW 2.0 and apply those to model band-structures. In addition, using a self-consistent fitting of the model parameters to experimental conductivity data, we provide a flexible tool to extract scattering rates with high accuracy. We illustrate the approximations using simple models and then apply the method to GaAs, Si, Mg3Sb2, and CoSb3.