• Dr. Nutan Kumari

The model employed in the theory of lattice dynamics based on any other phenomena is called the phenomenological model. The valence force field is employed in the vibrations of molecules in the fluid state this idea when applied in the solid-state vibration is called the valence force field. The present model developed for tetrahedrally bonded crystalline solids having zinc blende and diamond structure crystals. This phenomenological model in the present work is an extended valence force field model. The extended valence force field model had been applied to the lattice vibration of Germanium to obtain the theoretical values of the phonon dispersion curve along with three principal symmetry directions and Debye characteristic temperature at different temperatures. The calculated results are compared with the available experimental results.

Phenomenological model, Extended valence force field model, Phonon dispersion curve, Debye characteristic temperature

"Lattice dynamics of Germanium", International Journal of Emerging Technologies and Innovative Research (www.jetir.org), ISSN:2349-5162, Vol.4, Issue 2, page no.286-292, February-2017, Available :http://www.jetir.org/papers/JETIR1702046.pdf

"Lattice dynamics of Germanium", International Journal of Emerging Technologies and Innovative Research (www.jetir.org | UGC and issn Approved), ISSN:2349-5162, Vol.4, Issue 2, page no. pp286-292, February-2017, Available at : http://www.jetir.org/papers/JETIR1702046.pdf