Europhys. Lett.
Volume 70, Number 3, May 2005
Page(s) 362 - 368
Section Condensed matter: electronic structure, electrical, magnetic, and optical properties
Published online 06 April 2005
Europhys. Lett., 70 (3), pp. 362-368 (2005)
DOI: 10.1209/epl/i2005-10008-4

Boundary effect on CDW: Friedel oscillations, STM image

B. Dóra

Department of Physics, Budapest University of Technology and Economics H-1521 Budapest, Hungary

received 19 January 2005; accepted in final form 17 March 2005
published online 6 April 2005

We study the effect of open boundary condition on charge density waves (CDW). The electron density oscillates rapidly close to the boundary, and additional non-oscillating terms ( $\sim\ln(r)$) appear. The Friedel oscillations survive beyond the CDW coherence length ( $v_F/\Delta$), but their amplitude gets heavily suppressed. The scanning tunneling microscopy image (STM) of CDW shows clear features of the boundary. The local tunneling conductance becomes asymmetric with respect to the Fermi energy, and considerable amount of spectral weight is transferred to the lower gap edge. Also it exhibits additional zeros reflecting the influence of the boundary.

71.45.Lr - Charge-density-wave systems.
68.37.Ef - Scanning tunneling microscopy (including chemistry induced with STM).
73.40.Gk - Tunneling.

© EDP Sciences 2005