We present detailed investigations of the vibrational modes in a three-dimensional diatomic Penrose lattice. The vibrational densities of states are calculated using a recursion technique. These spectra show an apparently branched structure, we classify the branches by means of the same convention as used for crystals. The acoustic branches appear to be smooth and continuous and exhibit a linear feature near zero frequency, while the optical-like branches display a rich structure. The results demonstrate that the density of states in the acoustic branches can be attributed to the phonon and the fracton-like excitations and that in the optical-like branches to some localized vibrational modes.
部门归属
acad sinica,int ctr mat phys,shenyang 110015,peoples r china.;hu, y (reprint author), wuhan univ,dept phys,wuhan 430072,peoples r china
修改评论