Condensed-Matter Physics & Materials Science Seminar

"Soft x-ray spectroscopy calculations beyond the one body picture"

Presented by Oana Bunau, Institut de Minéralogie et de Physique des Milieux condensés (IMPMC), Paris, France

Friday, January 20, 2012, 11:00 am — Small Seminar Room, Bldg. 510

For more than 10 years, theorists from different groups in the world have tried to improve the description (via simulations) of the low energy absorption edge. In particular, the L23 edges of the 3d elements are sensitive to the electronic and magnetic properties of the compounds involved in applications. The ultimate aim is to get an unified description that joins the advantages of many body, parametrized methods and the ab initio, one body techniques as the DFT methods in the local density approximation. The latter are sensitive to band properties but unable to describe the essential many body effects, needed for the description of the vast majority of compounds. One of the possible solutions to this problem can be found in the time dependent density functional theory (TDDFT).

I will present a fully relativistic, full potential TDDFT method for the calculation of soft X-ray spectroscopy (e.g. absorption, resonant
scattering) in extended systems. I will show results at the L23 edges of the transition elements in metals and oxides. Various local approximations of the exchange - correlation kernel will be discussed.
Peculiar relativistic and non-spherical effects will be exposed, as well as a detailed study of the method's limitations and range of applicability.

Hosted by: John P. Hill

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