State-of-the-art in first-principles calculations of carrier transport properties in semiconductors: Methods, software, and applications to 3D and 2D materials*

One of the fundamental properties of semiconductors is their ability to support electric currents in the presence of electric and magnetic fields. These properties are described by transport coefficients such as drift and Hall electron and hole mobilities. During the past decade, there has been considerable progress in first-principles atomic-scale calculations of these coefficients by combining density functional theory, many-body perturbation theory, and the Boltzmann transport equation [1]. The reliability, accuracy, and reproducibility of these calculations keep improving at a fast pace, and we are at a point where state-of-the-art methods and software carry (nearly) predictive power. In this talk, I will review the formalism leading to the ab initio Boltzmann transport equation, and discuss the key approximations and the computational challenges of this approach. I will describe the Boltzmann transport solver of the software package EPW [2], and new methodological developments to investigate electron-phonon scattering in 2D materials [3] and ionized impurity scattering [4]. To illustrate this methodology, I will report on recent work on strain-engineering the hole mobility of GaN, and on the high-throughput search for high-mobility n-type and p-type 2D channel materials for nanoscale transistors. I will also discuss recent progress on the description of materials where strong electron-phonon interactions lead to the formation of localized polarons [5].