Localization and pair breaking parameter in superconducting molybdenum nitride thin films.

Area of Science:

• Condensed Matter Physics
• Materials Science
• Thin Film Technology

Background:

• Superconductor-insulator transitions are crucial for understanding quantum phenomena in materials.
• Molybdenum nitride films are promising candidates for studying these transitions due to their tunable properties.

Purpose of the Study:

• To investigate the superconductor-insulator transition in molybdenum nitride films.
• To analyze the role of localization theory and thermal fluctuations in this transition.

Main Methods:

• Fabrication of molybdenum nitride films via deposition onto MgO substrates.
• Measurement of critical temperature (Tc) and normal state sheet resistance (R_sheet).
• Analysis using Finkel'stein formula, localization theory, and thermal fluctuation correction terms (Aslamazov-Larkin and Maki-Thompson).

Main Results:

• Superconducting transition temperature (Tc) depression was observed with increasing sheet resistance, consistent with Finkel'stein formula.
• A critical sheet resistance (R_c) for the transition was identified.
• Excess conductance due to thermal fluctuations agreed well with theoretical models, despite some deviations in specific dependencies.

Conclusions:

• Localization theory provides a good framework for understanding the superconductor-insulator transition in these films.
• Deviations observed in thermal fluctuation analysis warrant further investigation.
• The study contributes to the understanding of quantum phase transitions in thin film superconductors.