{
  "id": "1806.09642",
  "version": "v1",
  "published": "2018-06-25T18:00:24.000Z",
  "updated": "2018-06-25T18:00:24.000Z",
  "title": "Chiral Optical Response of Multifold Fermions",
  "authors": [
    "Felix Flicker",
    "Fernando de Juan",
    "Barry Bradlyn",
    "Takahiro Morimoto",
    "Maia G. Vergniory",
    "Adolfo G. Grushin"
  ],
  "comment": "19+12 pages, 8+1 figures",
  "categories": [
    "cond-mat.mes-hall",
    "cond-mat.mtrl-sci",
    "cond-mat.str-el"
  ],
  "abstract": "Multifold fermions are generalizations of two-fold degenerate Weyl fermions with three-, four-, six- or eight-fold degeneracies protected by crystal symmetries, of which only the last type is necessarily non-chiral. Their low energy degrees of freedom can be described as emergent particles not present in the Standard Model of particle physics. We propose a range of experimental probes for multifold fermions in chiral symmetry groups based on the gyrotropic magnetic effect (GME) and the circular photo-galvanic effect (CPGE). We find that, in contrast to Weyl fermions, multifold fermions can have zero Berry curvature yet a finite GME, leading to an enhanced response. The CPGE is quantized and independent of frequency provided that the frequency region at which it is probed defines closed optically-activated momentum surfaces. We confirm the above properties by calculations in symmetry-restricted tight binding models with realistic density functional theory parameters. We identify a range of previously-unidentified ternary compounds able to exhibit chiral multifold fermions of all types (including a range of materials in the families AsBaPt and Gd3Cl3C), and provide specific predictions for the known multifold material RhSi.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2018-06-25T18:00:24.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "multifold fermions",
      "chiral optical response",
      "defines closed optically-activated momentum",
      "closed optically-activated momentum surfaces",
      "realistic density functional theory parameters"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 12,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}