Probing d-wave pairing correlations in the pseudogap regime of the cuprate superconductors via low-energy states near impurities

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关键词: T-C SUPERCONDUCTORS;    PHASE FLUCTUATIONS;    UNDERDOPED BI2SR2CACU2O8+DELTA;    SURFACE-STATES;    SYMMETRY;    EXCITATIONS;    SCATTERING;    DENSITY;    FILMS;    MODEL;   

DOI  :  10.1103/PhysRevB.64.224518

来源: SCIE

【 摘 要 】

The issue of probing the pseudogap regime of the cuprate superconductors, specifically with regard to the existence and nature of superconducting pairing correlations of d-wave symmetry, is explored theoretically. It is shown that if the d-wave correlations believed to describe the superconducting state persist into the pseudogap regime, but with pair-potential phase fluctuations that destroy their long-range nature, then the low-energy quasiparticle states observed near extended impurities in the truly superconducting state should also persist as resonances in the pseudogap regime. The scattering of quasiparticles by these phase-fluctuations broadens what was (in the superconducting state) a sharp peak in the single-particle spectral function at low energy, as we demonstrate within the context of a simple model. This peak and its broadening are, in principle, accessible via scanning tunneling spectroscopy near extended impurities in the pseudogap regime, If so, such experiments would provide a probe of the extent to which d-wave superconducting correlations persist upon entering the pseudocap regime, thus providing a stringent diagnostic of the phase-fluctuation scenario,

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