2010/06/07 by S. A. Chambers, S.A. Chambers, M. H. Engelhard +19 · 271 citations
Engineering · Materials Science · Physics and Astronomy · #Band offset #Density functional theory #Dipole #Discontinuity (linguistics) #Electric field #Electronic and Structural Properties of Oxides #Electronic band structure #Electronic structure #Epitaxy #Ferroelectric and Piezoelectric Materials #Heterojunction #Semiconductor materials and devices #cond-mat.mtrl-sci
paper · pdf · doi:10.1016/j.surfrep.2010.09.001
published in Surface Science Reports 65(10-12), 317-352 (Elsevier BV)
arxiv created 2010/06/07 · crossref issued 2010/10/01 · crossref published 2010/10/01 · crossref published-print 2010/10/01 · openalex publication_date 2010/10/01 · crossref created 2010/10/19 · arxiv updated 2015/05/19 · openalex created_date 2016/06/24 · crossref deposited 2025/09/28 · crossref indexed 2026/08/04 · openalex updated_date 2026/08/05
The question of stability against diffusional mixing at the prototypical LaAlO3/SrTiO3(001) interface is explored using a multi-faceted experimental and theoretical approach. We combine analytical methods with a range of sensitivities to elemental concentrations and spatial separations to investigate interfaces grown using on-axis pulsed laser deposition. We also employ computational modeling based on the density function theory as well as classical force fields to explore the energetic stability of a wide variety of intermixed atomic configurations relative to the idealized, atomically abrupt model. Statistical analysis of the calculated energies for the various configurations is used to elucidate the relative thermodynamic stability of intermixed and abrupt configurations. We find that on both experimental and theoretical fronts, the tendency toward intermixing is very strong. We have also measured and calculated key electronic properties such as the presence of electric fields and the value of the valence band discontinuity at the interface. We find no measurable electric field in either the LaAlO3 or SrTiO3, and that the valence band offset is near zero, partitioning the band discontinuity almost entirely to the conduction band edge. Moreover, we find that it is not possible to account for these electronic properties theoretically without including extensive intermixing in our physical model of the interface. The atomic configurations which give the greatest electrostatic stability are those that eliminate the interface dipole by intermixing, calling into question the conventional explanation for conductivity at this interface - electronic reconstruction. Rather, evidence is presented for La indiffusion and doping of the SrTiO3 below the interface as being the cause of the observed conductivity.