Layer by Layer Growth of Solid ⁴He on Graphite down to 0.1 K

The growth of solid ⁴He on graphite from the superfluid phase is known to occur at pressures well below the bulk solidification point. The number of adsorbed layers increases with pressure and the solid growth undergoes non-continuous layerby-layer growth at low temperature. We have studied this growth using the torsional oscillator method for isotherms down to 0.1 K. In contrast with simple layer-by-layer growth scenarios, our evidence suggests that the growth of adsorbed solid ⁴He is more complex and less solid is present on the graphite substrate at low temperature.