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Lecture A. Stoyanova

Rooster

WanneerWaar
29 oktober 2009 FWN-Building 5116.0136, Nijenborgh 4, 9747 AG, Groningen
Speaker: Dr. A. Stoyanova
Affiliation: Max-Planck-Institut für Physik komplexer Systeme, Dresden
Title: Correlation-induced corrections to the band structure of solids
Date: Thu Oct 29, 2009
Start: 11.00
Location: FWN-Building 5116.0136
Host: R. Broer and R. Havenith
Telephone: +31 50 363 4374

Abstract

A significant effort has been directed towards the design of formalisms for the accurate treatment of electron correlation effects in periodic systems. Algorithms based on density functional theory (DFT) have been refined to incorporate relevant correlation contributions to the electronic structure of solids. Such refinements lead, for example, to the optimized effective potential method or the time-dependent DFT. Correlation methods such as the dynamical mean field theory and the GW approximation have been also explored. The DFT-based schemes have provided hitherto valuable insights in the electronic structure of metallic as well as covalent and ionic compounds. Some of the most exploited approximations to DFT, the local density approximation and the generalized gradient approximation, yield however fundamental band gaps of semiconductors and insulators that are systematically underestimated. This enduring problem can be only partially attributed to the approximate exchange-correlation functionals. An alternative approach to the correlation problem in solids has been searched for in deriving and employing quantum chemical wave-function-based methods, such as the local Hamiltonian approach (LHA). The LHA is an ab initio local correlation method which utilizes local operators associated with real-space localized Hartree-Fock (HF) Wannier orbitals. Within this formalism, the correlation treatment is performed on finite fragments embedded in the infinite frozen HF environment. We discuss in this talk the LHA formalism and its extension to partially ionic heteropolar semiconductors.

Laatst gewijzigd:22 oktober 2012 14:30