Pressure induced lattice instability and phase separation in the cuprates

Abstract

Cite this article as: E. Liarokapis, D. Lampakis, E. Siranidi and M. Calaniotou, Pressure induced lattice instability and phase separation in the cuprates, Journal of Physics and Chemistry of Solids, doi:10.1016Solids, doi:10. /j.jpcs.2010 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. A c c e p t e d m a n u s c r i p t ABSTRACTHigh pressure structural studies using a synchrotron source and Raman measurements on various cuprates reveal several structural modifications. The data have shown strong deviations from the normal equation of state at characteristic pressures, hysteresis, and the appearance of additional peaks that can be attributed to a new phase. The combined data of synchrotron angle-dispersive experiments with the optical measurements indicate that at some critical pressures, at least for certain compounds, non-linear effects are observed together with phase separation that affect the distribution of the carriers and the transition temperature. The comparison of the data with those induced by an internal pressure by an atomic substitution indicates that the effect is related to the existence of carriers within the CuO 2 superconducting planes.

Non-linear lattice response of Sm oxypnictides to hydrostatic pressure

“…This is the same pressure limits where the Fe and As phonons show the anomaly (Fig.3) indicating that the reason of this effect is a doping dependent anisotropic response of the two axis to pressure and more specifically a non-monotonic compression of the superconducting FeAs 4 layer [17], apparently modifying the distribution of the carriers. In addition, our results provide a further indication for the connection of this effect to doping with the data pointing to a local lattice instability very similar to those observed before by high pressure studies in the cuprates [2,3,20]. Although more data are necessary to verify the tendency to local structural modifications and their dependence on doping, the absence of a similar effect in the non-superconducting SmFeAsO (Fig.1) and PrBa 2 Cu 3 O 7 [3] compounds are strong indications that the lattice distortions are directly related with doping.…”

“…tetrahedra. Our data on the oxypnictides are reminiscent of the anomalous non-linear behavior observed in the hydrostatic pressure Raman studies of the YBCO cuprates [20], which had been verified by synchrotron XRD measurements [2,3].…”

“…Besides, it can help the study of the superconductivity property and its relation to lattice by modifying the interatomic distances and driving the high T c superconductors towards or away from their lattice instabilities [2,3]. While there is an accumulated amount of data from these studies [1,4], the investigation of high-pressure effects on the Raman spectra is limited.…”

“…The effect of hydrostatic pressure on the transition temperature (T c ) of the high temperature superconductors has been used extensively [1], as it can indicate possible atomic substitutions for the preparation of compounds with higher T c . Besides, it can help the study of the superconductivity property and its relation to lattice by modifying the interatomic distances and driving the high T c superconductors towards or away from their lattice instabilities [2,3]. While there is an accumulated amount of data from these studies [1,4], the investigation of high-pressure effects on the Raman spectra is limited.…”

Phase separation instabilities and magnetism in two dimensional square and honeycomb Hubbard model

“…Thus, our phase diagram predicts the pressure induced transition also from AFI into PS phase and to metal phase. This phase diagram is consistent also with recently reported pressure and doping induced phase separations in cuprates [28][29][30]. There are questions related to the size of the AF or metallic domains when the system is phase separated.…”