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Disorder-Induced Quantum Griffiths Singularity Revealed in an Artificial 2D Superconducting System
Xiaowen Han1,2, Yufeng Wu1,2,3, Hong Xiao4
1State Key Laboratory of Functional Materials for Informatics Shanghai Institute of Microsystem and Information Technology Chinese Academy of Sciences 865 Changning Road Shanghai 200050 China.
Advanced Science (Weinheim, Baden-Wurttemberg, Germany)
|October 26, 2020
Summary
Disorder influences quantum phase transitions in 2D superconductors. Higher vortex pinning energy in graphene/Pb-island arrays correlates with the quantum Griffiths singularity, unlike graphene/Sn-island arrays.
Area of Science:
- Condensed Matter Physics
- Superconductivity
- Quantum Phase Transitions
Background:
- Disorder-induced Griffiths singularities are critical in 2D superconductors (2DSC).
- Vortex pinning energy is linked to disorder and quantum Griffiths singularities in superconductors.
- A direct link between vortex pinning energy and quantum Griffiths singularity in 2DSC requires further investigation.
Purpose of the Study:
- To investigate the role of vortex pinning energy in the quantum Griffiths singularity of 2D superconductors.
- To elucidate the relationship between disorder, vortex pinning, and quantum phase transitions in artificial 2D superconducting systems.
Main Methods:
- Fabrication of an artificial 2D superconductor using superconducting nanoislands (Pb) on 2D electron gas (graphene).
- Application of a vertical magnetic field to induce transitions in superconducting behavior.
- Analysis of vortex pinning energy using Arrhenius plot analysis.
- Comparison with graphene/Sn-islands-array hybrid systems.
Main Results:
- Quantum Griffiths singularity observed in the graphene/Pb-islands-array hybrid system.
- Superconducting behavior transitioned to weakly localized metallic behavior under a vertical magnetic field.
- The graphene/Pb-islands-array hybrid exhibited a greater vortex pinning energy compared to graphene/Sn-islands-array.
- A diverging dynamical critical exponent was observed as temperature approached zero.
Conclusions:
- Vortex pinning energy may play a significant role in the presence of quantum Griffiths singularity in 2D superconductors.
- The findings suggest a comprehensive interpretation for quantum phase transitions in 2D superconductors.
- Artificial superconducting systems offer a platform to study complex quantum phenomena.
Keywords:
2D electron gas (2DEG)disorderquantum Griffiths singularityquantum phase transition (QPT)vortex pinning energyMore Related Videos
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