"Phonon spectroscopy with sub-meV resolution by femtosecond x-ray diffuse scattering"

Diling Zhu: Aymeric Robert, Tom Henighan, Henrik T. Lemke, Matthieu Chollet, J. Mike Glownia, David A. Reis, and Mariano Trigo; Phys. Rev. B 92, 08/10/2015.

Additional Authors: Aymeric Robert, Tom Henighan, Henrik T. Lemke, Matthieu Chollet, J. Mike Glownia, David A. Reis, and Mariano Trigo

Abstract:

We present a reconstruction of the transverse acoustic phonon dispersion of germanium from femtosecond time-resolved x-ray diffuse scattering measurements at the Linac Coherent Light Source. We demonstrate an energy resolution of 0.3 meV with a momentum resolution of 0.01nm −1   using 10-keV x rays with a bandwidth of ∼1 eV . This high resolution was achieved simultaneously for a large section of reciprocal space including regions closely following three of the principal symmetry directions. The phonon dispersion was reconstructed with less than 3 h of measurement time, during which neither the x-ray energy, the sample orientation, nor the detector position were scanned. These results demonstrate how time-domain measurements can complement conventional frequency domain inelastic-scattering techniques.