Local vibrational modes of isolated hydrogen in germanium.

APPLIED PHYSICS REVIEWS Local vibrational modes of impurities in semiconductors

Omnipresent impurities such as carbon, oxygen, silicon, and hydrogen play important roles, both detrimental and beneficial, in the fabrication of solid-state devices. The electronic and vibrational properties of semiconductors are significantly altered by the presence of impurities. Atoms that are less massive than the host atoms, typically, show local vibrational modes ~LVMs!. Unlike lattice p...

Computational modeling of the size effects on the optical vibrational modes of H-terminated Ge nanostructures.

The vibrational dispersion relations of porous germanium (pGe) and germanium nanowires (GeNWs) were calculated using the ab initio density functional perturbation theory with a generalized gradient approximation with norm-conserving pseudopotentials. Both pores and nanowires were modeled using the supercell technique. All of the surface dangling bonds were saturated with hydrogen atoms. To addr...

The Structure and Chemical Bond of FOX-7: The AIM Analysis and Vibrational Normal Modes

FOX-7 (1,1-diamino-2,2-dinitroethylene) recently is expected as a relatively new energetic material with high-performance and low sensitivity. The RHF and MP2 levels and DFT method with B3LYP functional with aug-cc-pVDZ basis set have been used for obtaining equilibrium geometry and Rho function (electron density distribution). By the aid of fundamental physical theorems implemented in the ...

Rattling guest atoms in Si, Ge, and Sn-based type-II clathrate materials

We have studied the vibrational properties of some of the compounds based on the Type II silicon, germanium, and tin-based clathrate materials using LDA electronic structure methods. The lattices in these framework materials have open cages which can contain weakly bound guest impurities, and these guests produce local (“rattling”) vibrational modes. Such modes may scatter the extended, heat ca...

Theoretical investigation of the surface vibrational modes in germanium nanocrystals