Berlin 2015 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 96: Frontiers of Electronic Structure Theory: 2D TMDC and Excitonic Effects (organized by O)
TT 96.7: Talk
Thursday, March 19, 2015, 12:15–12:30, MA 004
Efficient exchange-correlation kernels for the description of excitonic effects in solids — •Santiago Rigamonti1,4, Silvana Botti2,4, Valérie Veniard3,4, Claudia Draxl1,4, Lucia Reining3,4, and Francesco Sottile3,4 — 1Physics Department, Humboldt-Universität zu Berlin, Germany — 2Friedrich-Schiller Universität Jena, Institut für Festkörpertheorie und -optik — 3Laboratoire des Solides Irradiés, École Polytechnique, CNRS, CEA-DSM, F-91128 Palaiseau, France — 4European Theoretical Spectroscopy Facility (ETSF)
One of the major challenges for time-dependent density-functional theory is the accurate and efficient description of excitonic effects in solids, captured by the exchange-correlation (xc) kernel. In a recent empirical approach, the so-called "bootstrap" kernel has been proposed. Due to its high efficiency and some promising results [1] it appeared indeed interesting. In this work, we find a physically motivated derivation for it, opening the way to understand its weaknesses and to propose a new xc kernel. Our kernel is both simpler and more reliable, as confirmed by our numerical results [2]. We also propose a simple method to estimate exciton binding energies from the dielectric functions computed in the random-phase approximation alone. This method makes the approach accessible to a wide range of scientists.
[1] S. Sharma, J. K. Dewhurst, A. Sanna, and E. K. U. Gross, Phys. Rev. Lett. 107, 186401 (2011).
[2] S. Rigamonti, S. Botti, V. Veniard, C. Draxl, L. Reining, and F. Sottile, submitted.