Interlayer correlation between two He 4 monolayers adsorbed on both sides of α -graphyne

摘要: Path-integral Monte Carlo calculations have been performed to study the $^{4}\mathrm{He}$ adsorption on both sides of a single $\ensuremath{\alpha}$-graphyne sheet. For investigation interlayer correlation between upper and lower monolayers adatoms, $^{4}\mathrm{He}$-substrate interaction is described by sum $^{4}\mathrm{He}\text{\ensuremath{-}}\mathrm{C}$ interatomic pair potentials for which we use Lennard-Jones Yukawa-6 anisotropic potentials. When layer ${\mathrm{C}}_{4/3}$ commensurate solid, upper-layer atoms are found form kagome lattice structure at Mott-insulating density $0.0706\phantom{\rule{0.28em}{0ex}}{\AA{}}^{\ensuremath{-}2}$ solid an areal $0.0941\phantom{\rule{0.28em}{0ex}}{\AA{}}^{\ensuremath{-}2}$ substrate The upper- lower-layer pseudospins, were introduced in Kwon et al. [Phys. Rev. B 88, 201403(R) (2013)] two degenerate configurations three hexagonal cell, depends potential used; with based potentials, Ising pseudospins layers be antiparallel each other whereas parallel pseudospin alignments nearly This attributed difference distance, $\ensuremath{\sim}4\phantom{\rule{0.28em}{0ex}}\AA{}$ but as large $\ensuremath{\sim}4.8\phantom{\rule{0.28em}{0ex}}\AA{}$ potential.