Edge Superfluidity of ⁴He Droplet and Half Layer on Graphite

Previous works suggest the edge of an incomplete layer of ⁴He on graphite is superfluid, however they were not conclusive given the small system sizes. We work in the grand canonical ensemble, which allows us to control the chemical potential leading to more efficient simulations and bigger system sizes. Our simulations show superfluid behavior in the edges of a droplet and a half-layer. In particular, the height-height correlation function of the edges of the half-layer indicates the edge is close to the Transverse Quantum Fluid (TQF) regime. Given that all experimental evidence of TQF in any system is indirect, ⁴He droplets on graphite offer a unique opportunity to study this state experimentally.