title: Van der Waals density functional for layered structures.
abstract: To understand sparse systems, we must account for both strong local atom bonds and weak nonlocal van der Waals forces between atoms separated by empty space. A fully nonlocal functional form [Phys. Rev. B 62, 6997 (2000)]] of density-functional theory (DFT) is applied here to the layered systems graphite, boron nitride, and molybdenum sulfide to compute bond lengths, binding energies, and compressibilities. These key examples show that the DFT with the generalized-gradient approximation does not apply for calculating properties of sparse matter, while use of the fully nonlocal version appears to be one way to proceed.
authors.affiliation: Department of Applied Physics, Chalmers University of Technology and Göteborg University, SE-412 96 Göteborg, Sweden.
authors.forename: H
authors.initials: H
authors.lastname: Rydberg
authors.forename: M
authors.initials: M
authors.lastname: Dion
authors.forename: N
authors.initials: N
authors.lastname: Jacobson
authors.forename: E
authors.initials: E
authors.lastname: Schröder
authors.forename: P
authors.initials: P
authors.lastname: Hyldgaard
authors.forename: S I
authors.initials: SI
authors.lastname: Simak
authors.forename: D C
authors.initials: DC
authors.lastname: Langreth
authors.forename: B I
authors.initials: BI
authors.lastname: Lundqvist