Calculation of Raman- and infrared-active modes of Tl/sub 2/CaBa/sub 2/Cu/sub 2/O/sub 8/

Journal Article · Tue Aug 01 00:00:00 EDT 1989 · Phys. Rev. B: Condens. Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.40.2642· OSTI ID:5947566

Kulkarni, A D; Prade, J; de Wette, F W; Kress, W; Schroder, U

We present the frequencies and polarizaton vectors of the infrared- and Raman-active modes forTl/sub 2/CaBa/sub 2/Cu/sub 2/O/sub 8/ (Tl 2:1:2:2). Our calculations are carried out in the framework of shell models, which are based on short-range overlap and long-range Coulomb potentials, as well as ionic polarizabilities. A guiding principle of this work is that the shell models for the different superconducting compounds should be mutually compatible, i.e., the short-range potentials for given ion pairs in equivalent environments should be transferable from one compound to the other. The optical data presented here for Tl 2:1:2:2 are obtained with a model which is applicable not only for six different thallium superconductors, but also for Bi/sub 2/CaSr/sub 2/Cu/sub 2/O/sub 8/ and YBa/sub 2/Cu/sub 3/O/sub 7/. The model for Tl 2:1:2:2 reproduces the measured infrared and Raman data quite well and yields a reliable first approximation for the displacement patterns of the modes at the /Gamma/ point. This is far from trivial since a mere force constant fit to the measured eigenvalues may yield rather arbitrary eigenvectors.

• Research Organization: Department of Physics, University of Texas, Austin, Texas 78712-1081 (US); Max-Planck-Institut fur Festkorperforschung, Postfach 80 06 65, D-7000 Stuttgart 80, Federal Republic of Germany; Universitat Regensburg, D-8400 Regensburg, Federal Republic of Germany
• OSTI ID: 5947566
• Journal Information: Phys. Rev. B: Condens. Matter; (United States), Journal Name: Phys. Rev. B: Condens. Matter; (United States) Vol. 40:4; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
BARIUM OXIDES
CALCIUM COMPOUNDS
CALCIUM OXIDES
CHALCOGENIDES
COPPER COMPOUNDS
COPPER OXIDES
INFRARED SPECTRA
OSCILLATION MODES
OXIDES
OXYGEN COMPOUNDS
PHONONS
QUASI PARTICLES
RAMAN EFFECT
SPECTRA
SUPERCONDUCTORS
THALLIUM COMPOUNDS
THALLIUM OXIDES
TRANSITION ELEMENT COMPOUNDS