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Calculation and interpretation of classical turning surfaces in solids

Aaron Kaplan1*, Stewart Clark2*, Kieron Burke3,4*, John Perdew1,5*

1 Department of Physics, Temple University, Philadelphia, PA 19122, USA

2 Centre for Materials Physics, Durham University, Durham, DH1 3LE, United Kingdom

3 Department of Chemistry, University of California, Irvine, CA 92697, USA

4 Department of Physics, University of California, Irvine, CA 92697, USA

5 Department of Chemistry, Temple University, Philadelphia, PA 19122, USA

* Corresponding authors emails: kaplan@temple.edu, s.j.clark@durham.ac.uk, kieron@uci.edu, perdew@temple.edu
DOI10.24435/materialscloud:2h-zq [version v1]

Publication date: Dec 22, 2020

How to cite this record

Aaron Kaplan, Stewart Clark, Kieron Burke, John Perdew, Calculation and interpretation of classical turning surfaces in solids, Materials Cloud Archive 2020.169 (2020), doi: 10.24435/materialscloud:2h-zq.


Classical turning surfaces of Kohn-Sham potentials separate classically-allowed regions (CARs) from classically-forbidden regions (CFRs). They are useful for understanding many chemical properties of molecules, but need not exist in solids, where the density never decays to zero. At equilibrium geometries, we find that CFRs are absent in perfect metals, rare in covalent semiconductors at equilibrium, but common in ionic and molecular crystals. In all materials, CFRs appear or grow as the internuclear distances are uniformly expanded. They can also appear at a monovacancy in a metal. Calculations with several approximate density functionals and codes confirm these behaviors. A classical picture of conduction suggests that CARs should be connected in metals, and disconnected in wide-gap insulators, and is confirmed in the limits of extreme compression and expansion. Surprisingly, many semiconductors have no CFR at equilibrium, a key finding for density functional construction. Nonetheless, a strong correlation with insulating behavior can still be inferred. Moreover, equilibrium bond lengths for all cases can be estimated from the bond type and the sum of the classical turning radii of the free atoms or ions. This record contains machine readable data for this work

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File name Size Description
6.0 KiB Contains metadata and file lists for tarballs
196.9 MiB PBE equilibrium solid data, in VASP
7.9 GiB PBE data as a function of unit cell volume, in VASP
23.3 KiB PBE data as a function of unit cell volume, in Castep
141.4 MiB LSDA equilibrium solid data, in VASP
2.1 GiB LSDA data as a function of unit cell volume, in VASP
2.9 KiB Sample HDF5 file reader that prints all group identifiers (keys) and a list of subgroup data and their attributes. Also includes an example of how the CFR volume would be calculated using this data.


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density functional theory turning surface DFT Kohn-Sham potential

Version history:

2020.169 (version v1) [This version] Dec 22, 2020 DOI10.24435/materialscloud:2h-zq