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TT: Fachverband Tiefe Temperaturen

TT 83: SrTiO₃: A Versatile Material from Bulk Quantum Paraelectric to 2D Superconductor III (joint session TT/KFM/MA/O)

TT 83.9: Talk

Friday, March 22, 2024, 11:45–12:00, H 0104

Effect of confinement and coulomb interactions on the electronic structure of the (111) LaAlO₃/SrTiO₃ interface — •Mattia Trama^1,2,3, Vittorio Cataudella^4,5, Carmine Antonio Perroni^4,5, Francesco Romeo¹, and Roberta Citro^1,2 — ¹Universitá degli Studi di Salerno, Fisciano, Italy — ²INFN Sezione di Napoli, Naples, Italy — ³Institute for Theoretical Solid State Physics, IFW Dresden, Dresden, Germany — ⁴Universitá degli Studi di Napoli Federico II, Naples, Italy — ⁵CNR-SPIN Napoli Unit, Naples, Italy

A tight-binding supercell approach is used for the calculation of the electronic structure of the (111) LaAlO₃/SrTiO₃ interface. The confinement potential at the interface is evaluated solving a discrete Poisson equation by means of an iterative method. In addition to the effect of the confinement, local Hubbard electron-electron terms are included at the mean-field level within a fully self-consistent procedure. The calculation carefully describes how the two dimensional electron gas arises from the quantum confinement of electrons near the interface due to the band bending potential. The resulting electronic sub-bands and Fermi surfaces show full agreement with the electronic structure determined by angle-resolved photoelectron spectroscopy experiments. In particular, we analyse how the effect of local Hubbard interactions change the density distribution over the layers from the interface to the bulk. Interestingly, the two-dimensional electron gas at the interface is not depleted by local Hubbard interactions which indeed induce an enhancement of the electron density between the first layers and the bulk.

Keywords: Oxide heterostructure; Coulomb interaction; Poisson-Schrödinger; Electronic band structure; Tight-binding