Europhys. Lett.
Volume 69, Number 5, March 2005
Page(s) 784 - 790
Section Condensed matter: electronic structure, electrical, magnetic, and optical properties
Published online 26 January 2005
Europhys. Lett., 69 (5), pp. 784-790 (2005)
DOI: 10.1209/epl/i2004-10403-3

Confinement of Bloch waves in $\chem{YSi_2}$ nanostructures on $\chem{Si(111)}$

L. Magaud1, G. Reinisch1, A. Pasturel2, P. Mallet1, E. Dupont-Ferrier1 and J.-Y. Veuillen1

1  LEPES-CNRS - BP 166, 38042 Grenoble cedex 9, France
2  LPM2C-CNRS - BP 166, 38042 Grenoble cedex 9, France

received 27 September 2004; accepted in final form 22 December 2004
published online 26 January 2005

Two-dimensional $\chem{YSi_2}$ or $\chem{ErSi_2}$ layers on $\chem{Si(111)}$ surface present two surface states in the vicinity of the Fermi level and form a two-dimensional surface electron gas. We have performed density functional theory (DFT) calculations of a realistic one-dimensional nanostructure of $\chem{YSi_2}$ on $\chem{Si(111)}$ to study confinement effects of this electron gas. The calculated square modulus of the wave function shows complex modulations related to the quantum interference patterns observed by scanning tunneling microscopy (STM). For each quantised state, the modulation involves at least three components consistent with the scattering of Bloch waves. A Fourier analysis of the real space modulations is used to construct the surface states dispersion curves. They are compared to the direct calculation of the ideal $\chem{YSi_2/Si(111)}$ surface electronic structure and to the E(k) curves deduced from conductance images in STM experiments.

73.20.At - Surface states, band structure, electron density of states.
72.10.Fk - Scattering by point defects, dislocations, surfaces, and other imperfections (including Kondo effect).
71.15.Mb - Density functional theory, local density approximation, gradient and other corrections.

© EDP Sciences 2005