Effect of strain on the stability and electronic properties of ferrimagnetic Fe2−xTixO3 heterostructures from correlated band theory

Based on density functional theory calculations including an on-site Hubbard U term, we investigate the effect of substrate-induced strain on the properties of ferrimagnetic hematite-ilmenite solid solutions and heterostructures. While the charge compensation mechanism through formation of a mixed Fe2+, Fe3+-contact layer is unaffected, strain can be used to tune the electronic properties of the system, e.g., by changing the position of impurity levels in the band gap. Straining Fe2O3–FeTiO3 films at the lateral lattice parameters of Al2O3(0001), commonly used as a substrate, is found to be energetically unfavorable as compared to films on Fe2O3(0001) or FeTiO3(0001)-substrates.