Structural characterization of a Cu/MgO(001) interface using CS-corrected HRTEM

Epitaxial Cu(001) layers were deposited on MgO(001) substrates by magnetron sputtering and the atomic structure of the Cu–MgO interface was characterized by spherical aberration (CS)-corrected high-resolution transmission electron microscopy (HRTEM). The interface structure and the misfit dislocation network were determined by imaging in both the b100N and b110N directions. The dislocation network was found to lie along the b100N directions with a Burgers vector of ½ aCu b100N deduced from HRTEM images and geometrical phase analysis. The dislocations do not fully accommodate the lattice mismatch, yielding residual stress at the interface and an elongation of the Cu lattice along the [001] direction