Elsevier, Physica C: Superconductivity and its Applications, 1-2(242), p. 46-54
DOI: 10.1016/0921-4534(94)02413-8
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In this paper we report Raman results from a high-quality c oriented ultra-thin layer (YBa2Cu3O7)2/(PrBa2Cu3O7)1 superconducting superlattice. In addition to bulk-like modes a new line is observed at a low temperature in the region around 320 cm?1 which is interpreted as originating from the antiphase combination of original IR active B1u phonons in individual YBa2Cu3O7 layers. We explain the Raman intensity of such a combined IR mode proposing the mixing of normal vectors and an asymmetric crystal field at Y---Pr interfaces.