摘要
We revisit the problem of adsorption of a single^(4)He layer on graphene,focusing on the commensurate(C_(1/3))crystalline phase,specifically on whether it may possess a nonzero superfluid response,and on the existence of superfluid phases,either(metastable)liquid or vacancy-doped crystalline.We make use of canonical quantum Monte Carlo simulations at zero and finite temperature,based on a realistic microscopic model of the system.Our results confirm the absence of any superfluid response in the commensurate crystal,and that no thermodynamically stable uniform phase exists at lower coverage.No evidence of a possibly long-lived,metastable superfluid phase at C_(1/3)coverage is found.Altogether,the results of ground-state projection methods and finite-temperature simulations are entirely consistent.
