▎ 摘　　要

The low-temperature phase diagram of He-4 adsorbed on a single graphene sheet is studied by computer simulations of a system consisting of nearly a thousand helium atoms. In the first layer, two commensurate solid phases are observed with fillings 1/3 and 7/16, respectively, separated by a domain wall phase, as well as an incommensurate crystal at a higher coverage. No evidence of a thermodynamically stable superfluid phase is found for the first adlayer. Second-layer promotion occurs at a coverage of 0.111(4) angstrom(-2). In the second layer, two phases are observed, namely a superfluid and an incommensurate solid, with no commensurate solid intervening between these two phases. The computed phase diagram closely resembles that predicted for helium on graphite. DOI: 10.1103/PhysRevB.87.094514