Superfluidlike Mass Flow Through 8  μm Thick Solid ^{4}He Samples

Area of Science:

• Condensed Matter Physics
• Quantum Fluids

Background:

• Superfluidity in helium-4 (⁴He) is a quantum mechanical phenomenon.
• Previous studies explored mass flow in thicker solid ⁴He samples.

Purpose of the Study:

• To investigate superfluidlike mass flow in thin solid ⁴He samples.
• To characterize the pressure and temperature dependence of this flow.
• To compare findings with previous experiments on thicker samples.

Main Methods:

• Utilizing coin-shaped 8 μm thick solid ⁴He samples.
• Sandwiching samples between superfluid leads.
• Measuring mass flow rate and onset temperature under varying pressures (up to 30 bar).
• Employing thermal annealing to enhance flow.

Main Results:

• Observed superfluidlike mass flow from melting pressure to at least 30 bar.
• Onset temperature decreased from 1 K to 0.25 K with increasing pressure.
• Mass-flow rate was sample-dependent, enhanced by annealing, and decreased with temperature.
• Flow rate showed near-exponential decay with sample pressure.
• Dissipation decreased with temperature, becoming superfluidlike near 0.1 K.
• No sharp cutoff in mass-flow rate was observed at low temperatures, unlike in thicker samples.

Conclusions:

• Thin solid ⁴He samples exhibit robust superfluidlike mass flow over a significant pressure range.
• The observed behavior differs from thicker samples, particularly regarding the absence of a low-temperature cutoff.
• Findings provide new insights into quantum transport phenomena in solid helium.