Suppression of disorder broadening of core-level photoelectron lines in CuAu alloys by inhomogeneous lattice distortion
T. Marten, I. A. Abrikosov, W. Olovsson, B. Johansson, R. J. Cole, G. Beamson, S. R. Haines, and P. Weightman, Phys. Rev. B 79, 012201 (2009)
Local environment effects represent a signature of disorder in a non-periodic system. In an ideal periodic solid all atoms that occupy equivalent positions in the crystal unit cell have exactly the same properties. In a disordered system even chemically equivalent atoms are, strictly speaking, different. This is a fundamental property of non-periodic solids.
Disorder broadening of core-level binding energies is a general effect observed in random alloys, and identifies a new opportunity to study specific local environments experimentally.
Here we study it in an archetypical system: face centered cubic Cu50Au50. While the disorder broadening is clearly detectable at Au, at Cu it is below detection limit.
To the best of our knowledge, this is the first system where such a different behaviour for two alloy components has been observed. Based on the theoretical studies, we attribute the suppression of the disorder broadening of core level photoelectron lines of Cu to the presence of a delicate balance between the dispersion of the CLS induced by the different local chemical environments of Cu atoms in a random alloy and the influence of inhomogeneous lattice distortions.
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Last updated: 04/29/09