Year: 2020
Type: article
Abstract: When complex mechanisms are involved, pinpointing high-performance materials within large databases is a major challenge in materials discovery. We focus here on phonon-limited conductivities, and study 2D semiconductors doped by field effects. Using state-of-the-art density-functional perturbation theory and Boltzmann transport equation, we discuss 11 monolayers with outstanding transport properties. These materials are selected from a computational database of exfoliable materials providing monolayers that are dynamically stable and that do not have more than six atoms per unit cell. We first analyze electron-phonon scattering in two well-known systems: electron-doped InSe and hole-doped phosphorene. Both are single-valley systems with weak electron-phonon interactions, but they represent two distinct pathways to fast transport: a steep and deep isotropic valley for the former and strongly anisotropic electron-phonon physics for the latter. We identify similar features in the database and compute the conductivities of the relevant monolayers. This process yields several high-conductivity materials, some of them only very recently emerging in the literature (GaSe, Bi 2 SeTe 2 , Bi 2 Se 3 , Sb 2 SeTe 2 ), others never discussed in this context (AlLiTe 2 , BiClTe, ClGaTe, AuI). Comparing these 11 monolayers in detail, we discuss how the strength and angular dependency of the electron-phonon scattering drives key differences in the transport performance of materials despite similar valley structure. We also discuss the high conductivity of hole-doped WSe 2 , and how this case study shows the limitations of a selection process that would be based on band properties alone.
Source: 2D Materials
Authors: Thibault Sohier, Marco Gibertini, Nicola Marzari
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
Funders: National Science Foundation, Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung, Partnership for Advanced Computing in Europe AISBL, Fonds De La Recherche Scientifique - FNRS, National Center of Competence in Research Materials’ Revolution: Computational Design and Discovery of Novel Materials
OpenAlex ID: W3046544323