Thomas-Fermi model of electronic screening in semiconductor nanocrystalsD. Ninno1, F. Trani1, G. Cantele1, K. J. Hameeuw2, G. Iadonisi1, E. Degoli3 and S. Ossicini3
1 Coherentia CNR-INFM and Università di Napoli Federico II, Dipartimento di Scienze Fisiche, Complesso Universitario Monte S. Angelo - via Cintia, I-80126 Napoli, Italy
2 TFVS, Universiteit Antwerpen - Universiteitsplein 1, B-2610 Antwerpen, Belgium
3 CNR-INFM-S and Dipartimento di Scienze e Metodi dell'Ingegneria Università di Modena e Reggio Emilia - via Fogliani, I-42100 Reggio Emilia, Italy
received 29 November 2005; accepted in final form 28 February 2006
published online 22 March 2006
Using first-principle density-functional theory in the GGA approximation we have studied the electronic screening in semiconductor nanocrystals. Combining simple electrostatics and the Thomas-Fermi theory it is shown that an analytical and general form of a model position-dependent screening function can be obtained. Taking as a case study silicon nanocrystals, the relative weights of the nanocrystal core and surface polarization contribution to the screening are thoroughly discussed. The connection between the screening at the nanoscale and in the bulk is clarified.
78.67.Bf - Nanocrystals and nanoparticles.
71.45.Gm - Exchange, correlation, dielectric and magnetic response functions, plasmons.
© EDP Sciences 2006