Thickness-dependent nanofriction of a rare gas monolayer sliding on Pb(111) ultrathin films X. L. Cai, J. J. Wang, X. N. Fu, S. Y. Bai, C. Y. Niu and Y. Jia EPL, 113 4 (2016) 46002 Published online: 11 March 2016 DOI: 10.1209/0295-5075/113/46002