title: Quasiparticle dynamics and spin-orbital texture of the SrTiO3 two-dimensional electron gas.
abstract: Two-dimensional electron gases (2DEGs) in SrTiO3 have become model systems for engineering emergent behaviour in complex transition metal oxides. Understanding the collective interactions that enable this, however, has thus far proved elusive. Here we demonstrate that angle-resolved photoemission can directly image the quasiparticle dynamics of the d-electron subband ladder of this complex-oxide 2DEG. Combined with realistic tight-binding supercell calculations, we uncover how quantum confinement and inversion symmetry breaking collectively tune the delicate interplay of charge, spin, orbital and lattice degrees of freedom in this system. We reveal how they lead to pronounced orbital ordering, mediate an orbitally enhanced Rashba splitting with complex subband-dependent spin-orbital textures and markedly change the character of electron-phonon coupling, co-operatively shaping the low-energy electronic structure of the 2DEG. Our results allow for a unified understanding of spectroscopic and transport measurements across different classes of SrTiO3-based 2DEGs, and yield new microscopic insights on their functional properties.
authors.affiliation: 1] Kavli Institute at Cornell for Nanoscale Science, Ithaca, New York 14853, USA [2] SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews, Fife KY16 9SS, UK.
authors.forename: P D C
authors.initials: PD
authors.lastname: King
authors.affiliation: Département de Physique de la Matière Condensée, Université de Genève, 24 Quai Ernest-Ansermet, 1211 Genève 4, Switzerland.
authors.forename: S
authors.initials: S
authors.lastname: McKeown Walker
authors.affiliation: Département de Physique de la Matière Condensée, Université de Genève, 24 Quai Ernest-Ansermet, 1211 Genève 4, Switzerland.
authors.forename: A
authors.initials: A
authors.lastname: Tamai
authors.affiliation: Département de Physique de la Matière Condensée, Université de Genève, 24 Quai Ernest-Ansermet, 1211 Genève 4, Switzerland.
authors.forename: A
authors.initials: A
authors.lastname: de la Torre
authors.affiliation: School of Physics and NANOTEC-SUT Center of Excellence on Advanced Functional Nanomaterials, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand.
authors.forename: T
authors.initials: T
authors.lastname: Eknapakul
authors.affiliation: School of Physics and NANOTEC-SUT Center of Excellence on Advanced Functional Nanomaterials, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand.
authors.forename: P
authors.initials: P
authors.lastname: Buaphet
authors.affiliation: Advanced Light Source, Lawrence Berkeley National Lab, Berkeley, California 94720, USA.
authors.forename: S-K
authors.initials: SK
authors.lastname: Mo
authors.affiliation: School of Physics and NANOTEC-SUT Center of Excellence on Advanced Functional Nanomaterials, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand.
authors.forename: W
authors.initials: W
authors.lastname: Meevasana
authors.affiliation: 1] Quantum-Phase Electronics Center, Department of Applied Physics, The University of Tokyo, Tokyo 113-8656, Japan [2] RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan.
authors.forename: M S
authors.initials: MS
authors.lastname: Bahramy
authors.affiliation: 1] SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews, Fife KY16 9SS, UK [2] Département de Physique de la Matière Condensée, Université de Genève, 24 Quai Ernest-Ansermet, 1211 Genève 4, Switzerland [3] Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland.
authors.forename: F
authors.initials: F
authors.lastname: Baumberger
mesh_terms: D055598:Chemical Phenomena; D004583:Electrons; D005740:Gases / Q000737:chemistry*; D007700:Kinetics; D008956:Models, Chemical; D008958:Models, Molecular; D010087:Oxides / Q000737:chemistry*; D013324:Strontium / Q000737:chemistry*; D014025:Titanium / Q000737:chemistry*
chemical_list: D005740:Gases; D010087:Oxides; D014025:Titanium; C119252:strontium titanium oxide; D013324:Strontium