Strain-controlled epitaxial stabilization in ultrathin LaNiO₃ films grown by pulsed laser deposition

We report on the epitaxial stabilization effect of strain on the growth of ultrathin heterostructures of a correlated metal LaNiO₃ (10 unit cells, ∼3.84 nm; u.c. hereafter) grown on a series of perovskite oxide substrates with both tensile and compressive strain. An unusual polynomial dependence of the activation energy for surface relaxation processes in terms of the lattice misfit was observed. Our experimental investigations further demonstrate the influence of strain relaxation on the self-ordering of complex oxide compounds in the perovskite structure during high supersaturation monolayer (interrupted layer-by-layer) deposition.