{
  "id": "1511.05276",
  "version": "v1",
  "published": "2015-11-17T05:57:02.000Z",
  "updated": "2015-11-17T05:57:02.000Z",
  "title": "Spin Dynamics of Complex Oxides, Bismuth-Antimony Alloys, and Bismuth Chalcogenides",
  "authors": [
    "Cüneyt Şahin"
  ],
  "comment": "Thesis defended in July 15, 2015 at the University of Iowa",
  "categories": [
    "cond-mat.mes-hall"
  ],
  "abstract": "This thesis predicts that two types of material families could be a solution to the challenges in spintronics: complex oxides and bismuth based materials. We derive a general approach for constructing an effective spin-orbit Hamiltonian, which applies to all nonmagnetic materials. We also verify this formalism through comparisons with other approaches for III-V semiconductors. Its general applicability is illustrated by deriving the spin-orbit interaction and predicting spin lifetimes for strained SrTiO$_3$ and a two-dimensional electron gas (such as at the LaAlO$_3$/SrTiO$_3$ interface). Our results suggest robust spin coherence and spin transport properties in SrTiO$_3$ related materials. In the second part, we calculate intrinsic spin Hall conductivities for Bi$_{1-x}$Sb$_x$ semimetals with strong spin-orbit couplings, from the Kubo formula and using Berry curvatures evaluated from a tight-binding Hamiltonian. Nearly crossing bands with strong spin-orbit interaction generate giant spin Hall conductivities in these materials, ranging from 474 ($\\hbar/e)( \\Omega^{-1}cm^{-1}$) for bismuth to 96($\\hbar/e)( \\Omega^{-1}cm^{-1}$) for antimony; the value for bismuth is more than twice that of platinum. The large spin Hall conductivities persist for alloy compositions corresponding to a three-dimensional topological insulator state, such as Bi$_{0.83}$Sb$_{0.17}$. The spin Hall conductivity could be changed by a factor of 5 for doped Bi, or for Bi$_{0.83}$Sb$_{0.17}$, by changing the chemical potential, suggesting the potential for doping or voltage tuned spin Hall current. We also calculate intrinsic spin Hall conductivities of Bi$_2$Se$_3$ and Bi$_2$Te$_3$ topological insulators from an effective tight-binding Hamiltonian. We conclude that bismuth-antimony alloys and bismuth chalcogenides are primary candidates for efficiently generating spin currents through the spin Hall effect.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2015-11-17T05:57:02.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "spin hall conductivity",
      "bismuth-antimony alloys",
      "bismuth chalcogenides",
      "complex oxides",
      "spin-orbit interaction generate giant"
    ],
    "tags": [
      "dissertation"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}