Abstract
The thermomechanical effect in superfluid helium is used to create an initial chemical potential difference across a solid sample. This causes a flow of helium atoms from one reservoir filled with superfluid helium, through a sample cell filled with solid helium, to another superfluid-filled reservoir until chemical potential equilibrium between the reservoirs is restored. The solid helium sample is separated from each of the reservoirs by Vycor rods that allow only the superfluid component to flow. With an improved technique, measurements of the flow at several fixed solid helium temperatures have been made as a function of in the pressure range 25.5–26.1 bar, and measurements of have been made as a function of temperature in the range mK for several fixed values of . The temperature dependence of the flow above 100 mK shows a reduction of the flux with an increase in temperature that is well described by . The nonlinear functional dependence , with independent of temperature but dependent on pressure, documents in some detail the dissipative nature of the flow and suggests that this system demonstrates Luttinger liquid-like one-dimensional behavior. The mechanism that causes this flow behavior is not certain, but is consistent with superflow on the cores of edge dislocations.
7 More- Received 16 July 2014
- Revised 23 September 2014
DOI:https://doi.org/10.1103/PhysRevB.90.134511
©2014 American Physical Society