Diagrammatic Separation of Different Crystal Structures of A 2 BX 4 Compounds Without Energy Minimization: A Pseudopotential Orbital Radii Approach

• Published in: Advanced functional materials Vol. 20; no. 12; pp. 1944 - 1952
• Main Authors: Zhang, Xiuwen, Zunger, Alex
• Format: Journal Article
• Language: English
• Published: 23.06.2010
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.200901811

Abstract The A 2 BX 4 family of compounds manifest a wide range of physical properties, including transparent conductivity, ferromagnetism, and superconductivity. A 98% successful diagrammatic separation of the 44 different crystal structures of 688 oxide A 2 BX 4 compounds (96% for 266 oxide‐only) is described by plotting the total radius of the A atom R A versus the radius of the B atom R B for many A 2 BX 4 compounds of known structure types and seeking heuristically simple, straight boundaries in the R A versus R B plane that best separate the domains of different structure types. The radii are sums R A  =  R s (A) +  R p (A) of the quantum‐mechanically calculated “orbital radii” R s ( R p ), rather than empirical radii or phenomenological electronegativity scales. These success rates using first‐principles orbital radii uniformly exceed the success rates using classic radii. Such maps afford a quick guess of the crystal structure of a yet unmade A 2 BX 4 compound by placing its atomic orbital radii on such maps and reading off its structure type.