Lattice dynamics of high-T-c superconductor HgBa2Ca2Cu3O8 with Pb substitution

The lattice dynamical properties of HgBa2Ca2Cu3O8 (Hg-1233) with Pb substit ution have been investigated by using a simple lattice dynamical model theo ry, namely the unscreened rigid ion model. The results from the present cal culations show an overall consistent description of the lattice vibrations in this compound. We could not compare our results with experimental measur ements as they are not available so far. However, we have made an attempt t o compare the phonon properties of Pb-doped and undoped Hg-1223 compounds t o see the effect of Pb substitution on the phonon properties. We observe a significant shift in the peak positions and shape of the phonon density of states of Hg-1223, when it is doped with Pb. (C) 2000 Elsevier Science B.V. All rights reserved.