Evidence for symmetry breaking local distortions in Tl{sub 2}Ba{sub 2}NuO{sub 6}
- Los Alamos National Laboratory, NM (United States)
High temperature superconductors (HTSC) are perhaps the most extensively characterized materials of recent times. The average crystallographic structures have been determined by X-ray, neutron and electron diffraction techniques. Recent investigations using extended x-ray absorption fine structures (EXAFS) and pair distribution analysis (PDF), however, have shown that there are significant local deviations from the average crystallographic structure. These local structural anomalies have been observed in several systems, including YBa{sub 2}Cu{sub 3}O{sub 7}, Nd{sub 2-x}Ce{sub x}CuO{sub 4{minus}y}, Bi{sub 2}Ca{sub 2}SrCu{sub 2}O{sub 8}, and TlBa{sub 2}Ca{sub 3}Cu{sub 4}O{sub 11}. Comparison of the x-ray absorption near edge spectra (XANES) of several superconducting systems indicate that structural anomalies also exist in Tl{sub 2}Ba{sub 2}CuO{sub 6} (2201), and these anomalies reduce the crystal symmetry. The authors interpret this lowering of symmetry as an indication of the existence of localized states in this structure. Powder EXAFS experiments on the Tl based superconductors, as well as preliminary EXAFS results on oriented samples support this conclusion.
- Research Organization:
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
- OSTI ID:
- 68437
- Report Number(s):
- LA-UR-94-1148; CONF-931247-; ON: DE94009293; TRN: 94:004697-0019
- Resource Relation:
- Conference: Strongly correlated electronic materials, Los Alamos, NM (United States), 15-18 Dec 1993; Other Information: PBD: [1994]; Related Information: Is Part Of Proceedings, strongly correlated electronic materials: The Los Alamos symposium 1993; Bedell, K.S.; PB: 662 p.
- Country of Publication:
- United States
- Language:
- English
Similar Records
Is Tl sub 2 Ba sub 2 CuO sub 6 a superconductor - Metal array
Electronic Raman scattering in the single-CuO{sub 2} layered superconductor Tl{sub 2}Ba{sub 2}CuO{sub 6+{delta}}