Phase boundaries and critical and tricritical properties of monolayer 4He adsorbed on graphite.
We report heat-capacity measurements on 4He films adsorbed on graphite for surface densities at and smaller than that required to form a commensurate (√3 × √3 )R30° monolayer in the temperature range 0.4 K
Ecke, R.; Shu, Q.-S.; Sullivan, T.; and Vilches, O., "Phase boundaries and critical and tricritical properties of monolayer 4He adsorbed on graphite." (1985). Physical Review B 31(1): 448-455. Faculty Publications. Paper 313.
Physical Review B