Berlin 2008 – scientific programme

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O: Fachverband Oberflächenphysik

O 26: Methods: Electronic Structure Theory

O 26.1: Talk

Tuesday, February 26, 2008, 11:15–11:30, MA 042

Improved description of correlation energies within an ab-initio framework — •Judith Harl and Georg Kresse — Vienna University, Sensengasse 8/12, 1090 Vienna, Austria

A well known shortcoming of the standard exchange-correlation functionals (LDA and GGA) used in density functional theory is that they do not include long-range correlation and therefore fail to describe Van-der-Waals bonded systems accurately.

The adiabatic connection fluctuation-dissipation theorem (ACFDT) [1,2] provides an exact expression for the correlation energy depending on the system’s response function when switching from the Kohn-Sham to the full many-body Hamiltonian. ACFDT calculations for real systems, mostly within the random phase approximation (RPA), have become feasible recently (e.g. [3,4]).

In this work, we apply the ACFDT within the RPA to rare-gas solids and to a set of insulators and metals. Lattice constants and bulk moduli are improved compared to gradient corrected functionals with relative errors reduced by roughly a factor 2.

[1] D.C.Langreth, J.P.Perdew, Solid State Commun. 17, 1425 (1975).

[2] O.Gunnarsson, B.I.Lundqvist, Phys. Rev. B 13, 4274 (1976).

[3] F.Furche, Phys. Rev B 64, 195120 (2001).

[4] A.Marini et al., Phys. Rev. Lett. 96, 136404 (2006).