On the mixing of vibrational modes in high- Tc superconductors
Abstract
The mixing of oxygen vibrational modes of A 1g symmetry in the lattice of high- Tc superconductors with a common structural unit, the CuO 2 planes, has been studied. The polarization ratio in the Raman spectra of superconducting single crystals of YBa 2Cu 3O 7- x and Tl mBa 2Ca n-1 Cu nO 2( n+1)+ m is investigated and the coefficient of mode mixing for totally symmetric A 1g vibrations in YBa 2CuO 7- x and Tl 2Ba 2CaCu 2O 8- x crystals was determined from it. Both strong mode mixing and a single mechanism of excitation of both A 1g oxygen modes have been confirmed as applied to YBa 2CuO 7- x by the fact that they display a similar spectral dependence of the resonant Raman scattering intensity.
- Publication:
-
Physics Reports
- Pub Date:
- October 1990
- DOI:
- 10.1016/0370-1573(90)90038-4
- Bibcode:
- 1990PhR...194..387M