Destruction of superconductivity through phase fluctuations in ultrathin a-MoGe films

Article

关键词: PENETRATION DEPTH;    INSULATOR TRANSITION;    2-COIL APPARATUS;    TEMPERATURE;    CONDUCTIVITY;    LOCALIZATION;    AMPLITUDE;    DENSITY;    MODEL;   

DOI  :  10.1103/PhysRevB.102.060501

来源: SCIE

【 摘 要 】

Superconductivity occurs in metals when attractive interactions between electrons promote the formation of Cooper pairs which get locked in a phase-coherent state, leading to superfluid behavior. In situations where the phase stiffness falls below the pairing energy, the superconducting transition temperature T-c is driven by phase fluctuations and pairing can continue to survive above T-c. Such a behavior has long been thought of as the hallmark of unconventional superconductivity. Here we combine sub-K scanning tunneling spectroscopy, magnetic penetration depth measurements, and magnetotransport measurements to show that in ultrathin amorphous MoGe (a-MoGe) films the superfluid density is strongly suppressed by quantum phase fluctuations at low temperatures for thickness below 5 nm. This is associated with a rapid decrease in the superconducting transition temperature T-c and the emergence of a pronounced pseudogap above T-c. These observations suggest that even in conventional superconductors strong disorder and low dimensionality will ultimately trigger a Bosonic route for the destruction of superconductivity.

【 授权许可】

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