Self-assembly of neon into a quantum gel with crystalline structure in superfluid 4He:: Prediction from density functional theory

Doping superfluid (4)He with a low concentration of neon atoms is predicted to lead to the self-assembly of quantum gel with crystalline structure, where each atom is isolated by a mixture of liquid and solid helium. The formation of this structure is shown to originate from the repulsive or attractive interactions between the solvent shells surrounding the neon atoms. The lattice geometry for neon atoms is predicted to be very sensitive to many-body effects, but by assuming a simple cubic symmetry, an upper limit estimate for neon atom density can be established (7% of bulk neon). Based on the energy estimates, this quantum gel structure is not related to the previously observed neon impurity helium solid. Experimental aspects of the quantum gel preparation are also briefly discussed.