Ion blocking dip shape analysis around a LaAlO 3 /SrTiO 3 interface

Denis Jalabert (1) , Hicham Zaid (2) , Marie-Hélène Berger (2) , I. Fongkaew (3) , W.R.L. Lambrecht (4) , A. Sehirlioglu (4)

1 LEMMA - Laboratoire d'Etude des Matériaux par Microscopie Avancée
2 MAT - Centre des Matériaux
3 SUT - Suranaree University of Technology
4 Case Western Reserve University [Cleveland]

We present an analysis of the widths of the blocking dips obtained in MEIS ion blocking experiments of two LaAlO3/SrTiO3 heterostructures differing in their LaAlO3 layer thicknesses. In the LaAlO3 layers, the observed blocking dips are larger than expected. This enlargement is the result of the superposition of individual dips at slightly different angular positions revealing a local disorder in the atomic alignment, i.e., layer buckling. By contrast, in the SrTiO3 substrate, just below the interface, the obtained blocking dips are thinner than expected. This thinning indicates that the blocking atoms stand at a larger distance from the scattering center than expected. This is attributed to an accumulation of Sr vacancies at the layer/substrate interface which induces lattice distortions shifting the atoms off the scattering plane.

Mots clés: Real-space structural analysis; Ion blocking; MEIS; LaAlO3/SrTiO3interface; Cation vacancy

Domaines: Physique [physics]; Matière Condensée [cond-mat]; Science des matériaux [cond-mat.mtrl-sci]

Denis Jalabert, Hicham Zaid, Marie-Hélène Berger, I. Fongkaew, W.R.L. Lambrecht, et al.. Ion blocking dip shape analysis around a LaAlO 3 /SrTiO 3 interface. Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2018, 423, pp.67-71. ⟨10.1016/j.nimb.2018.03.010⟩. ⟨hal-01759211⟩