Doped holes in edge-shared chains and the dynamic spectral weight transfer in X-ray absorption spectroscopy

¹ Institut für Festkörper- und Werkstofforschung D-01171 Dresden, PF 270116, Germany
² Laboratorium für Festkörperphysik, ETH Zürich - CH-8057 Zürich, Switzerland
³ Institut für Experimentalphysik, Freie Universität Berlin Arnimallee 14, D-14195 Berlin-Dahlem, Germany
⁴ BESSY GmbH - Albert-Einsteinstr. 15, D-12489 Berlin, Germany

Corresponding author: drechsler@ifw-dresden.de

Received: 6 November 2001
Accepted: 2 April 2002

Abstract

We present a joint experimental and theoretical study of the electronic structure of the chain compounds ACuO₂ () using O-K and Cu-L₃ X-ray absorption spectroscopy. The doping-dependent behaviour in these systems differs from that of conventional 2D Cu-O networks formed by corner-shared CuO₄ plaquettes. It follows from the strongly weakened inter-plaquette hybridisation due to the nearly 90° Cu-O-Cu bond in the chains. Spectroscopically, this results in a) the different final states in the Cu-L₃ spectra which can be used directly to “read-off” the Cu valency and b) a drastic reduction in the dynamic spectral weight transfer from the upper Hubbard band to the low-energy scale in the O-K spectra.