RT Journal Article T1 Zero-temperature phase diagram of the second layer of 4He adsorbed on graphene A1 Gordillo, M.C. A1 Boronat, Jordi K1 Graphene K1 Zero temperature AB The phase diagram at zero temperature of 4He adsorbed on a helium incommensurate triangular solid on top of a single graphene sheet has been obtained using the diffusion Monte Carlo method. We have found that, in accordance with previous experimental and simulation results for graphite, the ground state of 4He on this setup is a liquid that, upon compression, transforms into a triangular solid. To define the stability limits of both liquid and solid phases, we considered not only the adsorption energies of the atoms located on the second layer but the average energy of the atoms in both layers. Our results show that the lower density limit for a stable liquid in the second layer is 0.163±0.005 Å¿2 and that the lower limit for the existence of an incommensurate solid on the second layer is 0.186±0.003 Å¿2. Both values are in overall agreement with the results of torsional oscillator experiments and heat capacity measurements on graphite. The 4/7 and 7/12 registered solids are found to be metastable with respect to triangular incommensurate arrangements of the same density. PB American Physical Society SN 1098-0121 YR 2012 FD 2012-05 LK http://hdl.handle.net/10433/907 UL http://hdl.handle.net/10433/907 LA en NO Physical Review B - Condensed Matter and Materials Physics, 2012;85(19) NO Universidad Pablo de Olavide. Departamento de Sistemas Físicos, Químicos y Naturales DS RIO RD May 24, 2026