Eur. Phys. J. B 6, 487-496 (1998)
https://doi.org/10.1007/s100510050575

X-ray spectroscopy of the metal-insulator transition in Yb_1-xGd_xTe and Yb_1-xLa_xTe

¹ Laboratoire de Chimie Métallurgique des Terres Rares, Centre National de la Recherche Scientifique, 1 place A. Briand, 92195 Meudon Cedex, France
² Laboratoire de Physico-Chimie de la Matière Condensée, Université des Sciences et Techniques du Languedoc, place Eugène Bataillon, 34095 Montpellier Cedex 5, France
³ Laboratoire des Milieux Désordonnés et Hétérogènes, Université Pierre et Marie Curie, 4 place Jussieu, 75251 Paris Cedex 05, France
⁴ Laboratoire de Physique des Solides, Centre National de la Recherche Scientifique, 1 place A. Briand, 92195 Meudon Cedex, France

Corresponding author: ^a mauger@aomc.jussieu.fr

Received: 23 March 1998
Accepted: 12 July 1998
Published online: 15 December 1998

Abstract

We report extended X-ray absorption fine structure (EXAFS) of Yb_1-xGd_xTe and Yb_1-xLa_xTe, two solid solutions which show an insulator-metal transition (IMT) as a function of x for a high donor concentration . The results are correlated to transport experiments and X-ray diffraction data, to analyse the IMT in relation to the structure at both a local and a macroscopic scale. A bimodal distribution is found for rare earth-Te nearest distances in these compounds crystallized in the fcc structure. In particular, we find the less rigid Yb–Te bond can be used as a local probe for the wavefunction of the electrons introduced by La or Gd donors, hence a new insight on the metal-insulator transitions which are of a different nature in the two solid solutions.