Vibrational Properties of Disorder Silicene
A large amount of work has been devoted to the calculation of the phonon density of states (PDOSs) in disordered systems. However, very little is known about the actual nature of phonon states. By analogy with the corresponding problem of electrons in disordered systems, one expect that for strong disorder, phonon states will be localized excitations in the Anderson sense .Phonon localization in one-dimensional solids has been considered by Ishii and Jackle .Numerical studies has been considered by Nagel, Rahman, and Grest, for Lenrand-Jones glasses The glasses were prepared by means of molecular dynamics simulations of rapid cooling from the liquid state. One a glass was formed, the normal modes of vibration were studied numerically. It was found that above a certain frequency the modes were localized, as expected from the general ideas of Anderson localization. The structural and vibrational properties of two-dimensional hexagonal silicon (silicene) are investigated by means of first-principles calculations. It is predicted that the silicene structure with a small buckling of 0.44 Å (0.7 Å) and bond lengths of 2.28 Å (2.44 Å) is energetically the most favourable, and it does not exhibit imaginary phonon mode.
