c-axis lattice dynamics in Bi-based cuprate superconductors

摘要: We present the results of a systematic study c-axis lattice dynamics in single-layer ${\mathrm{Bi}}_{2}{\mathrm{Sr}}_{2}{\mathrm{CuO}}_{6}$ (Bi2201), bilayer ${\mathrm{Bi}}_{2}{\mathrm{Sr}}_{2}{\mathrm{CaCu}}_{2}{\mathrm{O}}_{8}$ (Bi2212), and trilayer ${\mathrm{Bi}}_{2}{\mathrm{Sr}}_{2}{\mathrm{Ca}}_{2}{\mathrm{Cu}}_{3}{\mathrm{O}}_{10}$ (Bi2223) cuprate superconductors. Our is based on both experimental data obtained by spectral ellipsometry single crystals theoretical calculations. The calculations are carried out within framework classical shell model, which includes long-range Coulomb interactions short-range Buckingham form system polarizable ions. Using same set model parameters for Bi2201, Bi2212, Bi2223, we calculate frequencies Brillouin-zone center phonon modes ${A}_{2u}$ symmetry suggest mode eigenvector patterns. achieve good agreement between calculated eigenfrequencies values TO allows us to make reliable assignment all three Bi-based also our $\ensuremath{\Gamma}$-point ${A}_{1g}$ Bi2223 an that published Raman spectra. superconductivity-induced anomalies recently observed infrared resonant scattering spectra consistently explained with suggested assignment.