## Exciton spectroscopy of hexagonal boron nitride using non-resonant x-ray Raman scattering

Feng, Yejun
Soininen, J. A.
Ankudinov, A. L.
Cross, J. O.
Seidler, G. T.
Macrander, A. T.
Rehr, J. J.
Shirley, E. L.
##### Description
We report non-resonant x-ray Raman scattering (XRS) measurements from hexagonal boron nitride for transferred momentum from 2 to 9 $\mathrm{\AA}^{-1}$ along directions both in and out of the basal plane. A symmetry-based argument, together with real-space full multiple scattering calculations of the projected density of states in the spherical harmonics basis, reveals that a strong pre-edge feature is a dominantly $Y_{10}$-type Frenkel exciton with no other \textit{s}-, \textit{p}-, or \textit{d}- components. This conclusion is supported by a second, independent calculation of the \textbf{q}-dependent XRS cross-section based on the Bethe-Salpeter equation.
##### Keywords
Condensed Matter - Materials Science