Abstract
Path-integral Monte Carlo calculations have been performed to study the adsorption on both sides of a single -graphyne sheet. For investigation of the interlayer correlation between the upper and the lower monolayers of adatoms, the -substrate interaction is described by the sum of the interatomic pair potentials for which we use both Lennard-Jones and Yukawa-6 anisotropic potentials. When the lower layer is a commensurate solid, the upper-layer atoms are found to form a kagome lattice structure at a Mott-insulating density of and a commensurate solid at an areal density of for both substrate potentials. The correlation between upper- and lower-layer pseudospins, which were introduced in Kwon et al. [Phys. Rev. B 88, 201403(R) (2013)] for two degenerate configurations of three atoms in a hexagonal cell, depends on the substrate potential used; with the substrate potential based on the anisotropic Yukawa-6 pair potentials, the Ising pseudospins of both layers are found to be antiparallel to each other whereas the parallel and antiparallel pseudospin alignments between the two layers are nearly degenerate with the Lennard-Jones potentials. This is attributed to the difference in the interlayer distance, which is with the Yukawa-6 substrate potential but as large as with the Lennard-Jones potential.
- Received 15 April 2015
- Revised 11 June 2015
DOI:https://doi.org/10.1103/PhysRevB.92.035402
©2015 American Physical Society