Optical Properties of the Spin-Ladder Compound Sr_{14}Cu_{24}O_{41}

Abstract

We report the measurements of the pseudodielectric function, far-infrared reflectivity and Raman scattering spectra in Sr_{14}Cu_{24}O_{41} single crystal. We study the lattice and the spin dynamics of the Cu${}_2$O${}_3$ spin ladders and CuO${}_2$ chains of this compound. The ellipsometric and the optical reflectivity measurements yield the gap values of 1.4 eV, 1.86 eV, 2.34 eV (2.5 eV) for the ladders (chains) along the {\bf c}-axis and 2.4 eV along the {\bf a}-axis. The electronic structure of the Cu${}_2$O${}_3$ ladders is analyzed using tight-binding approach for the correlated electron systems. The correlation gap value of 1.4 eV is calculated with the transfer energy (hopping) parameters $t=t_0$=0.26 eV, along and perpendicular to legs, $t_{xy}$=0.026 eV (interladder hopping) and U=2.1 eV, as a Coulomb repulsion. The optical parameters of the infrared active phonons and plasmons are obtained by oscillator fitting procedure of the reflectivity spectra. Raman scattering spectra are measured at different temperatures using different laser line energies. The two-magnon peak is observed at about 2880 cm${}^{-1}$. At temperatures below 150 K the new infrared and Raman modes appear due to the charge ordering.

22 pages, 9 figures, Phys. Rev. B, to be published

References in corpus (4)

• Experiments on Ladders Reveal a Complex Interplay between a Spin-Gapped Normal State and Superconductivity
• The Spin Dynamics of the Spin Ladder, Dimer Chain Material Sr14Cu24O41
• Electronic States of doped spin ladders (Sr,Ca)14Cu24O41
• Raman Scattering from Magnetic Excitations in the Spin Ladder Compounds CaV2O5 and MgV2O5

Cited by in corpus (12)

• Raman Response in Antiferromagnetic Two-Leg S=1/2 Heisenberg Ladders
• Experimental observation of the crystallization of a paired holon state
• Differences Between Hole and Electron Doping of a Two-Leg CuO Ladder
• Raman Response of Magnetic Excitations in Cuprate Ladders and Planes
• Weak coupling of pseudoacoustic phonons and magnon dynamics in incommensurate spin ladder compound Sr14Cu24O41
• Optical studies of gap, hopping energies and the Anderson-Hubbard parameter in the zigzag-chain compound SrCuO2
• Magnetic excitations in SrCu2O3: a Raman scattering study
• Two-magnon Raman scattering in spin-ladder geometries and the ratio of rung and leg exchange constants
• Phonon and magnetic dimer excitations in Fe-based S=2 spin ladder compound BaFe${}_2$Se${}_2$O
• Charge collective modes in an incommensurately modulated cuprate
• Charge density waves in Sr_14-xCa_xCu_24O_41: electron correlations vs. structural effects
• Effects of Ca substitution on quasi-acoustic sliding modes in Sr${}_{14-x}$Ca${}_x$Cu${}_{24}$O${}_{41}$