Mori M, Khaliullin G, Tohyama T, Maekawa S. Origin of the spatial variation of the pairing gap in bi-based high temperature cuprate superconductors.
PHYSICAL REVIEW LETTERS 2008;
101:247003. [PMID:
19113656 DOI:
10.1103/physrevlett.101.247003]
[Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2008] [Indexed: 05/27/2023]
Abstract
Recently, scanning tunneling microscopy on the Bi-2212 cuprate superconductor has revealed a spatial variation of the energy gap that is directly correlated with a modulation of the apical oxygen position. We identify two mechanisms by which out-of-plane oxygens can modulate the pairing interaction within the CuO2 layer: a covalency between the x2-y2 band and apical p orbital, and a screening of correlation U by apical oxygen polarization. Both effects strongly depend on the apical oxygen position, and their cooperative action explains the experiment.
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