Quasiparticle Self-consistent GW Approximation as a Universal Framework for Electronic Structure

Add to your list(s) Download to your calendar using vCal

• Prof Mark v. Schilfgaarde, King's College London
• Thursday 26 April 2012, 14:15-15:15
• TCM Seminar Room, Cavendish Laboratory.

If you have a question about this talk, please contact Dr G Moller.

A new type of self-consistent scheme within the GW approximation is presented, which we call the quasiparticle self-consistent GW (QSGW) approximation. It is based on a kind of self-consistent perturbation theory, where the self-consistency is used to minimize the difference between the many-body and single-particle Hamiltonians. QSGW describes optical properties in a wide range of materials rather well, including cases where the local-density and LDA -based GW approximations fail qualitatively. Self-consistency dramatically improves agreement with experiment, and is sometimes essential. QSGW avoids some formal and practical problems encountered in conventional self-consistent GW, which will be discussed. It handles both itinerant and correlated electrons on an equal footing, without any ambiguity about how a localized state is defined, or how double-counting terms should be subtracted. Weakly correlated materials such as Na and sp semiconductors are described with uniformly high accuracy. Discrepancies with experiment are small and systematic, and can be explained in terms of the approximations made.

Its consistently high accuracy make QSGW a versatile method that can reliably predict critical energy band properties of graphene, CuInSe2, CaFe2As2 and NiO in a unified framework. Many other properties attendant to the electronic structure can be calculated, such as magnetic excitations, the Auger recombination process, the transmission through a metal-semiconductor contact. In principle it can serve both as a framework to construct effective Hamiltonians for many-body physics, and as an engine to build models for device design from first principles, with unprecedented reliability. How to do this in practice is a major challenge today. I will briefly present some discussion of each.

This talk is part of the Theory of Condensed Matter series.

This talk is included in these lists:

• All Cavendish Laboratory Seminars
• All Talks (aka the CURE list)
• Centre for Health Leadership and Enterprise
• Combined TCM Seminars and TCM blackboard seminar listing
• Featured lists
• Lennard-Jones Centre external
• ME Seminar
• Neurons, Fake News, DNA and your iPhone: The Mathematics of Information
• PMRFPS's
• School of Physical Sciences
• TCM Seminar Room, Cavendish Laboratory
• Theory of Condensed Matter
• Thin Film Magnetic Talks
• few29

Note that ex-directory lists are not shown.