Probing the Meissner Effect in Microscale Two-Dimensional van der Waals Superconductors

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Devices

Background:

• Two-dimensional (2D) van der Waals (vdW) superconductors are promising for quantum devices but challenging to study due to small volumes and weak signals.
• Traditional assessment relies on zero resistance, neglecting the Meissner effect, a key indicator of superconductivity.

Purpose of the Study:

• To demonstrate dynamic cantilever magnetometry (DCM) as a method for probing the intrinsic Meissner diamagnetism in 2D vdW superconductors.
• To establish a theoretical model for quantitative extraction of magnetization and susceptibility from DCM measurements.
• To validate superconductivity in 2D vdW materials through magnetic signatures.

Main Methods:

• Development of a theoretical model to quantitatively analyze magnetization and susceptibility from DCM data.
• Application of DCM to 2-methoxy-4-methyl-2,4-dinitro-1,5-pentadiene (2M-WS2) as a model 2D vdW superconductor.
• Measurement of magnetization hysteresis loops and magnetic susceptibility.

Main Results:

• A clear magnetization hysteresis loop characteristic of type-II superconductivity was observed in 2M-WS2.
• Magnetic susceptibility was detected down to 5.7 nm thickness, showing ~89.9% diamagnetic screening efficiency at 4.6 mT.
• DCM achieved high sensitivity: ~1.1 × 10^-17 A·m² for magnetization and ~9.4 × 10^-17 A·m²/T for susceptibility.

Conclusions:

• DCM is capable of detecting the Meissner effect in 2D vdW superconductors, providing crucial magnetic validation.
• The study highlights DCM's potential for characterizing superconductivity in low-dimensional materials.
• This technique opens new avenues for exploring unconventional superconductivity and developing low-power quantum devices.