Figure 1
APS/Alan Stonebraker

Figure 1: These illustrations show helium-3 (yellow) adsorbed on different substrates: (a) on the surface of bulk helium-4 represented in blue; (b) on the surface of graphite represented in gray; and (c) on a solid layer of helium-4 above a graphite surface. Recent experimental evidence with graphite and helium-4 on graphite indicate the formation of a 2D liquid phase in the adsorbed helium-3 near absolute zero—depicted in (d).