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PGI-1 Talk: Dr. Vincent Sacksteder

Ab initio electronic screening: A key to improved DFT accuracy and to new ab initio predictions

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09 Nov 2017 11:30
venue
PGI Lecture Hall

Royal Holloway University of London, GB

Abstract:

Density functional theory codes have focused on calculating ground state properties of static systems without external perturbations. It is well known from work on screened Hartree-Fock, GW, MP2, and RPA approximations that improved accuracy can be obtained by calculating the system's screening in response to perturbations. However these improvements are very computationally heavy, and often have been reserved to quantum chemistry codes.

We describe our work within the CASTEP plane-wave DFT code to calculate the spin-charge susceptibility, which describes the system's screening. Our method is computationally light: we are able to calculate the screening response to a perturbation with a time and memory cost similar to that of a traditional DFT calculation of the Kohn-Sham ground state. It also highly scalable on parallel computers. This capability allows calculations of screened Hartree-Fock and (in the near future) GW, more robust convergence of the DFT ground state calculation, and prediction of response properties. Our algorithm for screened Hartree-Fock and GW is new, and features a much reduced memory consumption. We finish by discussing how this approach could be used to calculate properties of spintronics materials, including charge and spin transport.

Contact

Prof. Dr. Stefan Blügel
Phone: +49 2461 61-4249
Fax: +49 2461 61-2850
email: s.bluegel@fz-juelich.de

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