Effects of strong disorder in strongly correlated superconductors

Article

关键词: METAL-INSULATOR-TRANSITION;    D-WAVE SUPERCONDUCTORS;    2-DIMENSIONAL ELECTRON-SYSTEMS;    DENSITY-OF-STATES;    ZN-SUBSTITUTION;    IMPURITIES;    BI2SR2CACU2O8+DELTA;    DEFECTS;    GAP;   

DOI  :  10.1103/PhysRevB.95.014516

来源: SCIE

【 摘 要 】

We investigate the effect of strong disorder on a system with strong electronic repulsion. In the absence of disorder, the system has a d-wave superconducting ground state with strong non-BCS features due to its proximity to a Mott insulator. We find that while strong correlations make superconductivity in this system immune to weak disorder, superconductivity is destroyed efficiently when disorder strength is comparable to the effective bandwidth. The suppression of charge motion in regions of strong potential fluctuation leads to the formation of Mott insulating patches, which anchor a larger nonsuperconducting region around them. The system thus breaks into islands of Mott insulating and superconducting regions, with Anderson insulating regions occurring along the boundary of these regions. Thus, electronic correlation and disorder, when both are strong, aid each other in destroying superconductivity, in contrast to their competition at weak disorder. Our results shed light on why zinc impurities are efficient in destroying superconductivity in cuprates, even though it is robust to weaker impurities.

【 授权许可】

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