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Scanning SQUID Study of Vortex Manipulation by Local Contact
Published on: February 1, 2017
Vortex properties of two-dimensional superconducting Pb films.
1Institute of Physics, The Chinese Academy of Sciences, Beijing 100190, People's Republic of China.
Summary
Investigating two-dimensional superconducting lead films using scanning tunnelling microscopy/spectroscopy revealed thickness-dependent electronic states and vortex lattice distortions. This study transitions from clean to dirty superconductivity limits due to interface scattering.
Area of Science:
- Condensed Matter Physics
- Materials Science
Background:
- Superconducting films exhibit unique electronic properties influenced by thickness and surface disorder.
- Vortex behavior in superconductors is crucial for understanding their response to magnetic fields.
Purpose of the Study:
- To investigate vortex behavior in two-dimensional superconducting lead (Pb) films.
- To analyze the evolution of electronic states within vortex cores as a function of film thickness.
- To understand the impact of film thickness and surface defects on superconductivity and vortex lattice formation.
Main Methods:
- Low temperature scanning tunnelling microscopy/spectroscopy (LT-STM/STS) was employed.
- Measurements were conducted on two-dimensional superconducting Pb films of varying thicknesses.
- Analysis focused on electronic states at the vortex core and vortex lattice structure.
Main Results:
- Electronic states within the vortex core evolve with film thickness.
- A transition from the clean to the dirty limit of superconductivity was observed, linked to decreased electronic mean free path from interface scattering.
- Magnetic field-dependent vortex core size was noted, even in this low-kappa superconductor.
- Weak pinning from surface defects resulted in a distorted hexagonal vortex lattice.
Conclusions:
- Film thickness significantly impacts the electronic properties and superconducting behavior of 2D Pb films.
- Interface disorder plays a critical role in the transition between clean and dirty superconducting limits.
- Surface defects influence vortex pinning and the resulting vortex lattice structure, leading to distortions.
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