@article{KCBP,
	Pub-num 	   = {203},
	Title 		   = {Classical turning surfaces in solids: When do they occur, and what do they mean?},
	Author 		   = {Aaron D. Kaplan, Stewart J. Clark, Kieron Burke, John P. Perdew},
	Abstract 	   = {Classical turning surfaces of Kohn-Sham potentials, separating
	classically-allowed regions (CARs) from classically-forbidden regions (CFRs),
	provide a useful and rigorous approach to understanding many chemical
	properties of molecules. Here we calculate such surfaces for several
	paradigmatic solids. Our study of perfect crystals at equilibrium geometries
	suggests that CFRs are absent in metals, rare in covalent semiconductors, but
	common in ionic and molecular crystals. A CFR can appear at a monovacancy in a
	metal. In all materials, CFRs appear or grow as the internuclear distances are
	uniformly expanded. 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. This classical picture is confirmed in the limits of extreme
	uniform compression of the internuclear distances, where all materials become
	metals without CFRs, and extreme expansion, where all materials become
	insulators with disconnected and widely-separated CARs around the atoms.},
%%	Doi 		   = {},
%%	Issn		   = {},
	Year 		   = {2020},
	Month 		   = {July},
	Journal		   = {Submitted},
%%	Volume 		   = {},
%%	Issue 		   = {},
%%	Number 		   = {},
%%	Pages 		   = {},
%%	Publisher 	   = {},
%%	Url 		   = {},
	arXiv		   = {2007.01925},
%%	keywords 	   = {}
%%}