Statistics of localized phase slips in tunable width planar point contacts

Area of Science:

• Condensed Matter Physics
• Materials Science

Background:

• Superconducting nanowires dissipate energy primarily through phase slips.
• Previous studies focused on long nanowires with random phase slip events.

Purpose of the Study:

• Investigate highly confined phase slips at the contact point of superconducting leads.
• Analyze thermally activated phase slips and switching current probability density functions.
• Identify distinct thermal regimes in nanoconstrictions.

Main Methods:

• In-situ shrinking of nanoconstrictions to study confined phase slips.
• Measurement of switching current (I_sw) to trigger phase slip avalanches.
• Analysis of thermal regimes based on constriction and bath temperatures.

Main Results:

• Observed highly confined phase slips at nanoconstrictions.
• Characterized thermally activated phase slips and switching current distributions.
• Unveiled two thermal regimes: efficient heat removal and hot spot formation.

Conclusions:

• Confined phase slips in nanoconstrictions exhibit unique behaviors.
• Understanding thermal regimes is crucial for interpreting dissipation mechanisms.
• Results are vital for designing and understanding superconducting devices.