Publication date: Mar 04, 2022
We develop a computationally efficient scheme to accurately determine finite-temperature band gaps. We here focus on materials belonging to the class ABX3 (A = Rb, Cs; B = Ge, Sn, Pb; and X = F, Cl, Br, I), which includes halide perovskites. First, an initial estimate of the band gap is provided for the ideal crystalline structure through the use of a range-separated hybrid functional, in which the parameters are determined nonempirically from the electron density and the high-frequency dielectric constant. Next, we consider two kinds of band-gap corrections to account for spin-orbit coupling and thermal vibrations including zero-point motions. In particular, the latter effect is accounted for through the special displacement method, which consists in using a single distorted configuration obtained from the vibrational frequencies and eigenmodes, thereby avoiding lengthy molecular dynamics. The sequential consideration of both corrections systematically improves the band gaps, reaching a mean absolute error of 0.17 eV with respect to experimental values. The computational efficiency of our scheme stems from the fact that only a single calculation at the hybrid-functional level is required and that it is sufficient to evaluate the corrections at the semilocal level of theory. Our scheme is particularly convenient for large-size systems and for the screening of large databases of materials. This entry provides the ideal atomic structures and the distorted atomic structures at certain temperature including zero-point motions, generated by special displacement method.
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|35.2 KiB||The archive includes the .cif file of 21 materials calculated in the paper referenced below. Those atomic structures are achieved from experiments.|
|401.0 KiB||The archive compiles the atomic configuration of the ideal structures and the two kinds of displaced structures accounting for zero-point renormalisation (ZPR) and ZPR+T. The atomic position of the ideal structures were fully relaxed at the PBE level by the code of CP2K, and the lattice constants were fixed by the experimental values. The displaced structures are generated by the special displacement method.|
|84.6 MiB||The archive includes the vibration calculations for each materials, produced the results of eigenmodes and eigenfrequencies. They are carried out from the code of CP2K.|