Scaling Analysis of Direct Superconductor-Insulator Transitions in Disordered Ultrathin Films of Metals

Research output: Chapter in Book/Report/Conference proceedingChapter

Abstract

Superconductor-insulator (SI) transitions of homogeneously disordered ultrathin quench-condensed films in many instances appear to be direct, without any intervening metallic regime. This is in contrast with what has been found in some other systems. These direct transitions have been analyzed using finite size scaling. The products of the dynamical critical exponent and the coherence length exponent found vary, depending upon the tuning parameter. They are approximately 1.3 for the thickness tuned SI transition, and approximately 0.7 for perpendicular and parallel magnetic field tuning. Charge tuning also yields 0.7. Assuming that the dynamical critical exponent is unity as is anticipated for systems with long range interactions, all of the transitions, except the thickness-tuned transition would appear to belong to the 3D XY universality class. This behavior is different from that observed for magnetic field tuned transitions of compounds such as InOx or TiN, or other metallic systems. The source of these differences is not known but may be due to differences in carrier density or structural or chemical disorder on a mesoscopic scale.

Original languageEnglish (US)
Title of host publicationConductor-Insulator Quantum Phase Transitions
PublisherOxford University Press
Volume9780199592593
ISBN (Electronic)9780191741050
ISBN (Print)9780199592593
DOIs
StatePublished - Sep 20 2012

Keywords

  • 3D XY universality class
  • Quantum critical points
  • Quantum phase transitions
  • Quench-condensed film
  • Scaling
  • Superconductor-insulator transitions
  • Ultrathin films

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