In this talk, I will illustrate through two examples how electronic and structural couplings at oxide interfaces can lead to exciting novel properties and 2D systems [1,2].
A striking example is the interface between LaAlO3 and SrTiO3, two good band insulators, which was found to be conducting , and, in some doping range, superconducting with a maximum critical temperature of about 300 mK . In this system, the thickness of the conducting layer is found to be a few nanometers at low temperatures. This electron liquid with low electronic density, typically 5 1013 electrons/cm2, and naturally sandwiched between two insulators is ideal for performing electric field effect experiments allowing the carrier density to be tuned and superconductivity to be switched on and off [5,6].
I will then discuss how a coupling of instabilities can be used to design artificial ferroelectric materials with a focus on vanadate-based structures [7,8]. In these structures, it was found that the competition between the strain state and the coupling of oxygen octahedra rotations leads to an interesting “transition layer” and a reorientation of the orthorhombic long axis. This transition layer may be a way to design a functional 2D interface.
You can download the slides here.
 J. Mannhart and D. Schlom, Science 327, 1607 (2010).
 P. Zubko, S. Gariglio, M. Gabay, P. Ghosez, and J.-M. Triscone, Annual Review : Condensed Matter Physics 2, 141 (2011).
 A. Ohtomo, H. Y. Hwang, Nature 427, 423 (2004).
 N. Reyren, S. Thiel, A. D. Caviglia, L. Fitting Kourkoutis, G. Hammerl, C. Richter, C. W. Schneider, T. Kopp, A.-S. Ruetschi, D. Jaccard, M. Gabay, D. A. Muller, J.-M. Triscone and J. Mannhart, Science 317, 1196 (2007).
 A. Caviglia, S. Gariglio, N. Reyren, D. Jaccard, T. Schneider, M. Gabay, S. Thiel, G. Hammerl, J. Mannhart, and J.-M. Triscone, Nature 456, 624 (2008).
 S. Gariglio, M. Gabay, and J.-M. Triscone, Research Update, APL Materials 4, 060701 (2016).
 See, for instance, J. M. Rondinelli and C. J. Fennie, Adv. Mater. 24, 1961 (2012)
 H. Meley et al. APL Materials 6, 046102 (2018)
Location: Stuckelberg, Ecole de Physique
Time: Friday 9 June 2023, 12:10 for pizza, 12:30 start discussion