12-06

Polar-discontinuity-retaining A-site intermixing and vacancies at SrTiO₃/LaAIO₃ interfaces, Physical Review B85 (2012) 045401-1 - 045401-5

V. Vonk, J. Huijben, D. Kukuruznyak, A. Stierle, H. Hilgenkamp, A. Brinkman and S. Harkema

Abstract: Our anomalous surface x-ray diffraction study of the interface between SrTiO₃(001) substrates and thin polar films of LaAlO₃ shows La/Sr interdiffusion leading to neutrally charged Sr_1−1.5xLa_xO layers. From a thickness of two unit cells, the LaAlO₃ film's interior retains its polar stacking sequence, which is compensated by a cationic compositional change of the substrate's terminating TiO₂ layer. While such valence-retaining A-site intermixing does not resolve the polar catastrophe, it may be a general feature at oxide interfaces influencing the electronic and magnetic properties.