8:00 AM–11:00 AM, Thursday, March 16, 2006
Baltimore Convention Center - 344
Sponsoring Unit:
DCMP
Chair: Serge M. Nakhmanson, Rutgers University
Abstract ID: BAPS.2006.MAR.U41.7
9:12 AM–9:24 AM
B.C. Larson
J.Z. Tischler
(ORNL)
Wei Ku
(BNL and SUNY, Stoney Brook)
Chii-Cheng Lee
(Tamkang Univ. Taiwan)
Oscar Restrepo
(Univ. TN, Knoxville)
A.G. Eguiluz
(Univ. TN, Knoxville and ORNL)
P. Zschack
(FS-MRL UIUC)
K.D. Finkelstein
(CHESS, Cornell Univ.)
Non-resonant inelastic x-ray scattering (NIXS) and energy- resolved Wannier function analysis have been used to probe the strongly correlated electronic structure of NiO and CoO. NIXS measurements of the dynamical structure factor s(q,w) as a function of momentum transfer q and frequency w have shown that dipole-forbidden, d-d excitations appear within the optical gap for large wavevectors (q $>$ 2/A), become the dominant structure in the loss spectra for q $>$ 3/A, and reach a maximum at q $\sim$ 7/A. In contrast to the loss-spectra observed in resonant-probe studies of NiO and CoO, non-resonant spectra show only two excitations that are highly anisotropic - strongest in the [111] direction and weakest (or missing) in the [001] direction. Energy-resolved Wannier function analyses of vertex matrix elements within LDA+U demonstrate that the anisotropy provides a sensitive measure of electronic symmetry-breaking in these atomic-like d-d excitations as a result of point-group symmetry selection rules.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2006.MAR.U41.7