Here, Eint and Ecomp represent the interface and compression energies per Å 2 , respectively. Note that we have to divide by 2A since the unit cell contains two identical interfaces. The compression energy Ecomp of a guest (deposit) metal can be derived from the energy difference between a bulk unit cell of the laterally compressed guest metal with the lattice constant of the host (substrate) metal Ebulk,comp and a bulk unit cell of the guest metal in its natural lattice. For direct comparison with Eint we again normalize the energy with respect to the surface area of the unit cell by dividing it by the surface are 2A.