Unveiling Resilient Superconducting Fluctuations in Atomically Thin NbSe_{2} through Higgs Mode Spectroscopy

Area of Science:

• Condensed Matter Physics
• Materials Science
• Superconductivity

Background:

• Atomically thin materials offer unique platforms for studying fundamental quantum phenomena.
• Superconductivity in two-dimensional materials like niobium diselenide (NbSe2) is a subject of intense research.
• Understanding the nature of emergent electronic states is crucial for next-generation technologies.

Purpose of the Study:

• To investigate the nature of superconductivity in atomically thin NbSe2.
• To characterize the anomalous metallic state induced by an out-of-plane magnetic field.
• To identify and study the superconducting Higgs mode in these ultrathin samples.

Main Methods:

• Combined electrical transport measurements.
• Optical spectroscopy.
• Application of out-of-plane magnetic fields.
• Analysis of longitudinal and Hall resistance.

Main Results:

• An anomalous metallic state emerges in thin NbSe2 under magnetic fields, with finite longitudinal and vanishing Hall resistance.
• A superconducting Higgs mode is established, indicating persistent superconducting fluctuations.
• These fluctuations withstand high reduced magnetic fields, suggesting robust local electron pairing.

Conclusions:

• The anomalous metallic state in thin NbSe2 exhibits particle-hole symmetry.
• The observed superconducting Higgs mode confirms the bosonic nature of locally paired electrons.
• These findings highlight the robustness of superconductivity in atomically thin materials.