Phys. Rev. B 69, 125402 (2004) [8 pages]Role of inversion symmetry and multipole effects in nonresonant x-ray Raman scattering from icosahedral B4CReceived 19 June 2003; published 8 March 2004 We report nonresonant x-ray Raman scattering (XRS) measurements for the icosahedral boron carbide B4C for transferred momentum q from 1 to 9 Å-1. The observed q-dependence together with site-specific ab initio calculations identify a near-edge peak in the XRS spectra as a p-type (Δl=1) exciton due to dominant boron occupation at the sole atomic site in the unit cell having inversion symmetry. This result constrains models of substitutional disorder in B4C, introduces a new application of XRS, and emphasizes the utility of full multiple scattering calculations of the site-specific projected density of states for interpretation of the near edge region of XRS spectra. © 2004 The American Physical Society URL:
http://link.aps.org/doi/10.1103/PhysRevB.69.125402
DOI:
10.1103/PhysRevB.69.125402
PACS:
61.72.Ss, 61.10.Ht, 71.35.-y
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