van der Waals density functionals built upon the electron-gas tradition: facing the challenge of competing interactions.
The theoretical description of sparse matter attracts much interest, in particular for those ground-state properties that can be described by density functional theory. One proposed approach, the van der Waals density functional (vdW-DF) method, rests on strong physical foundations and offers simple yet accurate and robust functionals. A very recent functional within this method called vdW-DF-cx [K. Berland and P. Hyldgaard, Phys. Rev. B 89, 035412 (2014)] stands out in its attempt to use an exchange energy derived from the same plasmon-based theory from which the nonlocal correlation energy was derived. Encouraged by its good performance for solids, layered materials, and aromatic molecules, we apply it to several systems that are characterized by competing interactions. These include the ferroelectric response in PbTiO3, the adsorption of small molecules within metal-organic frameworks, the graphite/diamond phase transition, and the adsorption of an aromatic-molecule on the Ag(111) surface. Our results indicate that vdW-DF-cx is overall well suited to tackle these challenging systems. In addition to being a competitive density functional for sparse matter, the vdW-DF-cx construction presents a more robust general-purpose functional that could be applied to a range of materials problems with a variety of competing interactions.
Microtechnology and Nanoscience, MC2, Chalmers University of Technology, SE-412 96 Göteborg, Sweden.
Kristian
K
Berland
Department of Physics, Wake Forest University, Winston-Salem, North Carolina 27109, USA.
Calvin A
CA
Arter
Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6114, USA.
Valentino R
VR
Cooper
Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
Kyuho
K
Lee
Department of Applied Physics, Chalmers University of Technology, SE-412 96 Göteborg, Sweden.
Bengt I
BI
Lundqvist
Microtechnology and Nanoscience, MC2, Chalmers University of Technology, SE-412 96 Göteborg, Sweden.
Elsebeth
E
Schröder
Department of Physics, Wake Forest University, Winston-Salem, North Carolina 27109, USA.
T
T
Thonhauser
Microtechnology and Nanoscience, MC2, Chalmers University of Technology, SE-412 96 Göteborg, Sweden.
Per
P
Hyldgaard