Europhys. Lett.
Volume 64, Number 3, November 2003
Page(s) 364 - 370
Section Condensed matter: structure, mechanical and thermal properties
Published online 01 November 2003
DOI: 10.1209/epl/i2003-00203-9
Europhys. Lett., 64 (3) , pp. 364-370 (2003)

Multilayer thermal expansion of $\chem{Be(0001)}$ determined from surface core level shifts

A. Baraldi1, 2, 3, S. Lizzit1, K. Pohl4, P. Hofmann5 and S. de Gironcoli6

1  Sincrotrone Trieste S.C.p.A. - S.S. 14 km 163.5, 34012 Trieste, Italy
2  Dipartimento di Fisica, Università di Trieste - Via Valerio 2, 34127 Trieste, Italy
3  Laboratorio TASC-INFM - S.S. 14 km 163.5, 34012 Trieste, Italy
4  Department of Physics, University of New Hampshire - Durham, NH 03824, USA
5  Institute for Storage Ring Facilities, University of Aarhus DK-8000 Aarhus C, Denmark
6  Scuola Internazionale Superiore di Studi Avanzati (SISSA) and INFM Via Beirut 2-4, I-34014, Trieste, Italy

(Received 27 May 2003; accepted in final form 25 August 2003)

We have determined the thermal expansion of the first three interlayer spacings of $\chem{Be(0001)}$ by comparing measured temperature-dependent surface core level shifts and surface state positions to values calculated with Density Functional Theory for different surface geometries. Our results reveal that, in the temperature range from 300 to 700 $\un{K}$, the 1st-to-2nd, 2nd-to-3rd and 3rd-to-4th interlayer coefficient of thermal expansion are $88\pm 15$, $-10\pm 15$ and $-6\pm 20 \times 10^{-6}$ $\un{K^{-1}}$, respectively. We have now set $\chem{Be(0001)}$ as a challenge for further theoretical improvements, since a complete theoretical understanding of surface thermal expansion does not exist.

68.35.Bs - Structure of clean surfaces (reconstruction).
65.40.De - Thermal expansion; thermomechanical effects.
79.60.Bm - Clean metal, semiconductor, and insulator surfaces.

© EDP Sciences 2003