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oai:uvadoc.uva.es:10324/653212025-02-13T09:52:37Zcom_10324_1158com_10324_931com_10324_894col_10324_1242

Weissker, Hans-Christian Huotari, Simo Bruneval, Fabien Sottile, Francesco Monaco, Giulio Krisch, Michael Olevano, Valerio Reining, Lucia Serrano Gutiérrez, Jorge We present an investigation of the dynamic structure factor and of the dielectric function εM(Q,ω) of the prototypical semiconductor silicon for finite momentum transfer, combining inelastic x-ray scattering experiments and ab initio calculations. In contrast with optical spectra, for finite momentum transfer time-dependent density-functional theory in the adiabatic local-density approximation together with lifetime broadening describes the physics of valence excitations correctly. Major structures in the spectra, governed by short-range crystal and exchange-correlation local-field effects, are strongly influenced by a mixing of transitions of positive and negative energies, in striking difference to spectra for vanishing momentum transfer. This mixing gives rise to a pronounced Fano asymmetry. 2024-01-30 2024-01-30 2006 info:eu-repo/semantics/article Phys. Rev. Lett. 97, 237602 (2006) 0031-9007 https://uvadoc.uva.es/handle/10324/65321 10.1103/PhysRevLett.97.237602 23 Physical Review Letters 97 1079-7114 eng info:eu-repo/semantics/openAccess American Physical Society