Vibrational modes in: Raman study and theory
- 23 June 2008
- journal article
- research article
- Published by American Physical Society (APS) in Physical Review B
- Vol. 77 (23), 235213
- https://doi.org/10.1103/physrevb.77.235213
Abstract
Polarized Raman spectra were measured for single crystals and polycrystalline grown by a vapor-liquid-solid method. A group-theoretical analysis of the selection rules governing the predicted dependence of the spectra on incoming and outgoing wave polarizations and propagation direction is presented. First-order Raman spectra corresponding to the zone center phonons are calculated from first principles using density functional perturbation theory. The Brillouin zone integrated density of phonon states is also calculated. Comparison of theory and experiment allows us to identify the symmetry modes. However, vibrational density of states features deviating from the pure spectrum are also visible in the experimental spectra and indicate some relaxation of momentum conservation rules. Differences in the experimental spectra under different polarization conditions are compared to the calculations. These differences allow us to identify different Raman tensor components as well as to obtain at least partial information on the modes. The much weaker polarization dependence in experiment than in theory, however, can at least in part be explained by using wurtzite-type selection rules. The observation of features explainable with wurtzite together with orthorhombic selection rules suggest that there is only partial ordering of the cations on their sublattice.
Keywords
This publication has 20 references indexed in Scilit:
- First-principles calculation of the zone center phonons in: Comparison with infrared dataPhysical Review B, 2007
- Structure and phonons ofPhysical Review B, 2005
- Nonlinear optical susceptibilities, Raman efficiencies, and electro-optic tensors from first-principles density functional perturbation theoryPhysical Review B, 2005
- Prospective investigations of orthorhombic ZnGeN2: synthesis, lattice dynamics and optical propertiesMaterials Science and Engineering B, 2001
- Ab initio pseudopotentials for electronic structure calculations of poly-atomic systems using density-functional theoryComputer Physics Communications, 1999
- Self-interaction correction to density-functional approximations for many-electron systemsPhysical Review B, 1981
- Groupe spatial et ordre des atomes de zinc et de germanium dans ZnGeN2Materials Research Bulletin, 1973
- Preparation et proprietes de ZnGeN2Materials Research Bulletin, 1970
- Self-Consistent Equations Including Exchange and Correlation EffectsPhysical Review B, 1965
- Inhomogeneous Electron GasPhysical Review B, 1964