Rhombohedral distortion analysis of ultra-thin Pt(111) films deposited under Ar-N₂ atmosphere

A rhombohedral analysis method for analysing the lattice distortion in a (111)-textured face-centred cubic film under rotationally symmetric stress is proposed. Because no material constants, such as diffraction elastic constants, are required, the expressions of the distortion, namely the angle and the lattice parameter, are universal and can be readily used to compare different films. Using this rhombohedral distortion analysis method, (111)-textured Pt films deposited under argon-nitrogen atmosphere are systematically investigated, and the thickness-dependent lattice deformation in as-deposited and annealed films is described by the two geometrical parameters of the rhombohedral cell.