Superfluid transition of the second layer of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si23.svg" display="inline" id="d1e153"><mml:msup><mml:mrow /><mml:mrow><mml:mn>4</mml:mn></mml:mrow></mml:msup></mml:math>He on graphite: Does substrate corrugation matter?

The second layer of 4He adsorbed on a graphite substrate is studied by Quantum Monte Carlo simulations. We make use microscopic model the fully accounting for its corrugation, and compare results to those obtained with smooth substrate. only effect corrugation ∼20% reduction value superfluid fraction top layer, in limit zero temperature. No evidence any commensurate (7/12) crystalline and/or “supersolid” phase found; transition temperature estimated be ∼0.75 K. discuss implication these findings interpretation recent experiments.