Superconductor to weak-insulator transitions in disordered tantalum nitride films

Article

关键词: QUANTUM DIFFUSION;    THIN-FILMS;    TEMPERATURE;    PHASE;    LOCALIZATION;    DISSIPATION;    TRANSPORT;    DUALITY;    METAL;    STATE;   

DOI  :  10.1103/PhysRevB.96.134522

来源: SCIE

【 摘 要 】

We study the two-dimensional superconductor-insulator transition ( SIT) in thin films of tantalum nitride. At zero magnetic field, films can be disorder-tuned across the SIT by adjusting thickness and film stoichiometry; insulating films exhibit classical hopping transport. Superconducting films exhibit a magnetic-field-tuned SIT, whose insulating ground state at high field appears to be a quantum-corrected metal. Scaling behavior at the field-tuned SIT shows classical percolation critical exponents zv approximate to 1.3, with a corresponding critical field H-c << Hc2, the upper critical field. The Hall effect exhibits a crossing point near H-c, but with a nonuniversal critical value rho(c)(xy) comparable to the normal-state Hall resistivity. We propose that high-carrier-density metals will always exhibit this pattern of behavior at the boundary between superconducting and (trivially) insulating ground states.

【 授权许可】

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