sumo: Command-line tools for plotting and analysis of periodic ab initio calculations

Abstract

Ab initio electronic structure modelling is capable of providing an insight into the fundamental properties of solid-state materials, at a resolution beyond that of experimental techniques.The optoelectronic properties of a compound are analysed through several key descriptions, including: density-of-states distributions, which provide information on the orbital character of bonding; band structure diagrams, which indicate carrier transport properties; and optical absorption spectra, which are used to assess the wavelengths of light a material will transmit or absorb.An understanding of these fundamental properties is crucial when selecting or optimising materials for particular applications, including photovoltaics (Ganose, Savory, & Scanlon, 2017), transparent conductors (Ganose & Scanlon, 2016), and thermoelectrics (Gorai, Stevanović, & Toberer, 2017).Most common ab initio calculation software for analysing crystalline materials with periodic boundary condictions, such as Vienna ab initio Simulation Package (VASP) (Kresse & Furthmüller, 1996) and Quantum Espresso (Giannozzi et al., 2009), write raw data which require post-processing to plot or convert into a human-readable format.Several packages exist that facilitate the creation and plotting of such diagrams.Python libraries, such as Python Materials Genomics (pymatgen) (Ong et al., 2013) and Atomic Simulation Environment (ase) (Larsen et al., 2017), provide powerful interfaces for plotting and data analysis but require the user to be proficient in Python to use effectively.Conversely, programs which provide a graphical user interface, such as p4vasp (Dubay, 2018) and XCrySDen (Kokalj, 1999), are easy to use but are not conducive to working on the command line.The purpose of this package is to provide an intermediate solution that is trivial to use but still provides the flexibility needed for a broad range of analysis modes.