We present a first-principles linear-response study of the phonon spectrum and dipole activity of the Si(111)2 x 1 surface. Our results are in good agreement with the experimental He-scattering results for the acoustic modes, as well as the electron-energy-loss data for the optical modes. We clarify a current controversy on the assignment of the electron-energy-loss peak at approximately 56 meV. We find that the dominant contribution to the loss peak is anisotropic and arises from a longitudinal-optical vibration of the surface chains. However, a small but non-negligible isotropic contribution comes from subsurface modes polarized perpendicular to the surface.
Surface phonons and dipole activity of Si(111)2×1 from ab initio calculations / Ancilotto, F; Selloni, A; Andreoni, W; Baroni, Stefano; Car, R; Parrinello, M.. - In: PHYSICAL REVIEW. B, CONDENSED MATTER. - ISSN 0163-1829. - 43:11(1991), pp. 8930-8933. [10.1103/PhysRevB.43.8930]
Surface phonons and dipole activity of Si(111)2×1 from ab initio calculations
Baroni, Stefano;
1991-01-01
Abstract
We present a first-principles linear-response study of the phonon spectrum and dipole activity of the Si(111)2 x 1 surface. Our results are in good agreement with the experimental He-scattering results for the acoustic modes, as well as the electron-energy-loss data for the optical modes. We clarify a current controversy on the assignment of the electron-energy-loss peak at approximately 56 meV. We find that the dominant contribution to the loss peak is anisotropic and arises from a longitudinal-optical vibration of the surface chains. However, a small but non-negligible isotropic contribution comes from subsurface modes polarized perpendicular to the surface.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.