Lattice instabilities, isotope effect, and high-Tcsuperconductivity inLa2−xBaxCuO4
| Autor: | Ronald E. Cohen, W. E. Pickett, Henry Krakauer |
|---|---|
| Rok vydání: | 1991 |
| Předmět: |
chemistry.chemical_classification
Physics Superconductivity Statistics::Theory Statistics::Applications Condensed matter physics Transition temperature General Physics and Astronomy Electronic structure Crystal structure Tetragonal crystal system chemistry Condensed Matter::Superconductivity Local-density approximation Electronic band structure Inorganic compound |
| Zdroj: | Physical Review Letters. 67:228-231 |
| ISSN: | 0031-9007 |
| DOI: | 10.1103/physrevlett.67.228 |
| Popis: | Unlike ${\mathrm{La}}_{2\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{Sr}}_{\mathit{x}}$${\mathrm{CuO}}_{4}$, ${\mathrm{La}}_{2\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{Ba}}_{\mathit{x}}$${\mathrm{CuO}}_{4}$, x\ensuremath{\sim}${\mathit{x}}_{\mathrm{cr}}$=0.12, undergoes a structural change to a low-temperature tetragonal (LTT) phase below 60 K, and this transformation is known to suppress ${\mathit{T}}_{\mathit{c}}$ drastically. We present self-consistent local-density-functional calculations for this system that indicate the ${\mathrm{CuO}}_{6}$ octahedrons are unstable to an X-point tilt in any direction, thereby leading to strongly anharmonic X-point vibrations. The LTT phase is most favored energetically, consistent with experiment. The effect of the LTT distortion on the electronic structure accounts for the suppression of ${\mathit{T}}_{\mathit{c}}$ in the LTT phase, and for the enhanced isotope effect at x=${\mathit{x}}_{\mathrm{cr}}$. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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