Number of observable features in the acoustic-Raman spectra of nanocrystals

Lucien Saviot (1) , Nicolas Combe (2, 3) , Adnen Mlayah (2, 3)

1 ICB - Laboratoire Interdisciplinaire Carnot de Bourgogne
2 CEMES - Centre d'élaboration de matériaux et d'études structurales
3 UT3 - Université Toulouse III - Paul Sabatier

Low-frequency Raman scattering spectra are presented for gold nanocrystals with diameters 3.5 and 13 nm. The frequencies of the Raman peaks but also their number are shown to vary with the nanocrystal size. These results are analyzed using both the continuous elastic medium approximation and an atomistic approach. We show that the number of atoms in the nanocrystal determines an upper limit of the number of observable Raman features. The frequency range in which the continuous elastic medium approximation is valid is defined by comparison with the calculations based on the atomistic approach.

Domaines: Autre [cond-mat.other]

Lucien Saviot, Nicolas Combe, Adnen Mlayah. Number of observable features in the acoustic-Raman spectra of nanocrystals. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2012, 85, pp.075405. ⟨10.1103/PhysRevB.85.075405⟩. ⟨hal-00668244⟩