Anomalously large gap anisotropy in the a - b plane of Bi 2 Sr 2 </…
1993; American Physical Society; Volume: 70; Issue: 10 Linguagem: Inglês
10.1103/physrevlett.70.1553
ISSN1092-0145
AutoresZhi‐Xun Shen, D. S. Dessau, B. O. Wells, David M. King, W. E. Spicer, A. J. Arko, D. S. Marshall, L. W. Lombardo, A. Kapitulnik, P. H. Dickinson, Sebastian Doniach, J. DiCarlo, T. Loeser, C. H. Park,
Tópico(s)Superconductivity in MgB2 and Alloys
ResumoSuperconducting gap anisotropy at least an order of magnitude larger than that of the conventional superconductors has been observed in the a-b plane of ${\mathrm{Bi}}_{2}$${\mathrm{Sr}}_{2}$${\mathrm{CaCu}}_{2}$${\mathrm{O}}_{8+\mathrm{\ensuremath{\delta}}}$ in angle-resolved photoemission spectroscopy. For samples with ${\mathit{T}}_{\mathit{c}}$ of 88 K, the gap size reaches a maximum of approximately 20 meV along the Cu-O bond direction, and a minimum of much smaller or vanishing magnitude 45\ifmmode^\circ\else\textdegree\fi{} away. The experimental data are discussed within the context of various theoretical models. In particular, a detailed comparison with what is expected from a superconductor with a ${\mathit{d}}_{\mathit{x}}^{2}$-${\mathit{y}}^{2}$ order parameter is carried out, yielding a consistent picture.
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