Evidence for onset of charge density wave in the La-based Perovskite superconductors
Recent studies have shown that structural instabilities play a vital role in high-T c superconductivity. We have used a local structural probe, extended X-ray absorption fine structure (EXAFS), to investigate the instability of the CuO2 plane in La-based high-T c perovskite systems. Temperature-dependent CuK-edge EXAFS spectra measured on single crystals of La1.85Sr0.15CuO4 (LSCO) and La2CuO4.1 (LCO) show a characteristic temperature (T ls ) where the local structure of the system diverges from the average one. This temperature coincides with a crossover temperature where the system shows anomalous metal-insulator transition in transport measurements. We have discussed the EXAFS results as an evidence for a particular phase transition of the system with segregation of localized and itinerant charge carriers in a short coherence charge density wave (CDW). A phase diagram for this CDW has been proposed.
Key WordsLanthanum copper oxide charge density wave EXAFS
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- 3.D. Pines,Tr. J. Phys. 20, 535 (1996) and references therein.Google Scholar
- 15.N. L. Saini, A. Lanzara, A. Bianconi, D. S.-L Law, A. A. Menovsky, and K. B. Garg, Proc. Int. Workshop on High-Temperature Superconductivity-Ten Years after Its Discovery, Dec. 16–21, 1996, Jaipur, India.Google Scholar