| Autor: |
Zhang R, Bursi L; Dipartimento di Fisica, Informatica e Matematica-FIM, Università di Modena e Reggio Emilia , I-41125 Modena, Italy.; Istituto Nanoscienze, Consiglio Nazionale delle Ricerche CNR-NANO , I-41125 Modena, Italy., Cox JD; ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology , 08860 Castelldefels, Barcelona, Spain., Cui Y, Krauter CM, Alabastri A, Manjavacas A; Department of Physics and Astronomy, University of New Mexico , Albuquerque, New Mexico 87131, United States., Calzolari A; Istituto Nanoscienze, Consiglio Nazionale delle Ricerche CNR-NANO , I-41125 Modena, Italy., Corni S; Istituto Nanoscienze, Consiglio Nazionale delle Ricerche CNR-NANO , I-41125 Modena, Italy.; Dipartimento di Scienze Chimiche, Università di Padova , I-35131 Padova, Italy., Molinari E; Dipartimento di Fisica, Informatica e Matematica-FIM, Università di Modena e Reggio Emilia , I-41125 Modena, Italy.; Istituto Nanoscienze, Consiglio Nazionale delle Ricerche CNR-NANO , I-41125 Modena, Italy., Carter EA, García de Abajo FJ; ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology , 08860 Castelldefels, Barcelona, Spain.; ICREA-Institució Catalana de Reserca i Estudis Avançats , Passeig Lluís Companys 23, 08010 Barcelona, Spain., Zhang H, Nordlander P |
| Abstrakt: |
A promising trend in plasmonics involves shrinking the size of plasmon-supporting structures down to a few nanometers, thus enabling control over light-matter interaction at extreme-subwavelength scales. In this limit, quantum mechanical effects, such as nonlocal screening and size quantization, strongly affect the plasmonic response, rendering it substantially different from classical predictions. For very small clusters and molecules, collective plasmonic modes are hard to distinguish from other excitations such as single-electron transitions. Using rigorous quantum mechanical computational techniques for a wide variety of physical systems, we describe how an optical resonance of a nanostructure can be classified as either plasmonic or nonplasmonic. More precisely, we define a universal metric for such classification, the generalized plasmonicity index (GPI), which can be straightforwardly implemented in any computational electronic-structure method or classical electromagnetic approach to discriminate plasmons from single-particle excitations and photonic modes. Using the GPI, we investigate the plasmonicity of optical resonances in a wide range of systems including: the emergence of plasmonic behavior in small jellium spheres as the size and the number of electrons increase; atomic-scale metallic clusters as a function of the number of atoms; and nanostructured graphene as a function of size and doping down to the molecular plasmons in polycyclic aromatic hydrocarbons. Our study provides a rigorous foundation for the further development of ultrasmall nanostructures based on molecular plasmonics. |
