title: Magnetism, Spin Texture, and In-Gap States: Atomic Specialization at the Surface of Oxygen-Deficient SrTiO_{3}.
abstract: Motivated by recent spin- and angular-resolved photoemission (SARPES) measurements of the two-dimensional electronic states confined near the (001) surface of oxygen-deficient SrTiO_{3}, we explore their spin structure by means of ab initio density functional theory (DFT) calculations of slabs. Relativistic nonmagnetic DFT calculations display Rashba-like spin winding with a splitting of a few meV and when surface magnetism on the Ti ions is included, bands become spin-split with an energy difference ∼100  meV at the Γ point, consistent with SARPES findings. While magnetism tends to suppress the effects of the relativistic Rashba interaction, signatures of it are still clearly visible in terms of complex spin textures. Furthermore, we observe an atomic specialization phenomenon, namely, two types of electronic contributions: one is from Ti atoms neighboring the oxygen vacancies that acquire rather large magnetic moments and mostly create in-gap states; another comes from the partly polarized t_{2g} itinerant electrons of Ti atoms lying further away from the oxygen vacancy, which form the two-dimensional electron system and are responsible for the Rashba spin winding and the spin splitting at the Fermi surface.
authors.affiliation: Institut für Theoretische Physik, Goethe-Universtät Frankfurt, 60438 Frankfurt am Main, Germany.
authors.forename: Michaela
authors.initials: M
authors.lastname: Altmeyer
authors.affiliation: Institut für Theoretische Physik, Goethe-Universtät Frankfurt, 60438 Frankfurt am Main, Germany.
authors.forename: Harald O
authors.initials: HO
authors.lastname: Jeschke
authors.affiliation: Laboratoire de Physique des Solides, Bat 510, Université Paris-Sud, 91405 Orsay, France.
authors.forename: Oliver
authors.initials: O
authors.lastname: Hijano-Cubelos
authors.affiliation: Laboratoire de Physique des Solides, Bat 510, Université Paris-Sud, 91405 Orsay, France.
authors.forename: Cyril
authors.initials: C
authors.lastname: Martins
authors.affiliation: I. Institut für Theoretische Physik, Universität Hamburg, 20355 Hamburg, Germany.|Institut für Keramische Hochleistungswerkstoffe, TU Hamburg-Harburg, D-21073 Hamburg, Germany.
authors.forename: Frank
authors.initials: F
authors.lastname: Lechermann
authors.affiliation: IFW Dresden, Helmholtzstraße 20, 01069 Dresden, Germany.
authors.forename: Klaus
authors.initials: K
authors.lastname: Koepernik
authors.affiliation: CSNSM, Univ. Paris-Sud, CNRS/IN2P3, Université Paris-Saclay, Bât 104 et 108, 91405 Orsay, France.
authors.forename: Andrés F
authors.initials: AF
authors.lastname: Santander-Syro
authors.affiliation: Laboratoire de Physique des Solides, Bat 510, Université Paris-Sud, 91405 Orsay, France.
authors.forename: Marcelo J
authors.initials: MJ
authors.lastname: Rozenberg
authors.affiliation: Institut für Theoretische Physik, Goethe-Universtät Frankfurt, 60438 Frankfurt am Main, Germany.
authors.forename: Roser
authors.initials: R
authors.lastname: Valentí
authors.affiliation: Laboratoire de Physique des Solides, Bat 510, Université Paris-Sud, 91405 Orsay, France.
authors.forename: Marc
authors.initials: M
authors.lastname: Gabay