{
  "id": "2004.07379",
  "version": "v1",
  "published": "2020-04-15T22:52:38.000Z",
  "updated": "2020-04-15T22:52:38.000Z",
  "title": "Controlling valley splitting and Polarization of dark- and bi-excitons in monolayer WS$_2$ by a tilted magnetic field",
  "authors": [
    "Fanyao Qu",
    "Helena Bragança",
    "Railson Vasconcelos",
    "Fujun Liu",
    "S-J Xie",
    "Hao Zeng"
  ],
  "journal": "2D Materials 6.4 (2019): 045014",
  "doi": "10.1088/2053-1583/ab2cf7",
  "categories": [
    "cond-mat.mes-hall",
    "cond-mat.mtrl-sci"
  ],
  "abstract": "We developed a comprehensive theoretical framework focusing on many-body effects of exciton species in monolayer WS$_2$, including bright and dark excitons, and intra- and inter-valley biexcitons, to investigate valley dynamics in monolayer WS$_2$ subjected to a tilted magnetic field B. In particular, the evolution of the exciton population densities and the many-body particle scatterings are considered to calculate the valley polarization (V P ) as a function of the magnetic field. We found valley splittings for the dark exciton and biexciton energy levels that are larger than those of bright excitons, of -0.23 meV/T. For example, -0.46 meV/T for dark excitons and -0.69 meV/T for bright-dark intra-valley biexcitons. Furthermore, inter-valley bright-dark excitons have an opposite valley energy splittings of +0.23 meV/T. For the samples pumped by linearly polarized light, V P exhibits distinct magnetic field dependence for different types of many-body particle states. Among them, the V P of the intra-valley bright-dark biexcitons increases with increasing magnetic field and reaches nearly 50% at B=65 T. The brightened dark exciton, on the other hand, exhibits vanishing VP, indicating long valley relaxation time. Remarkably, the inter-valley bright-dark biexciton shows unconventional behavior with an inverted VP. The opposite VP for intra- and inter-valley bright-dark biexcitons, coupled with their large valley splitting and long valley lifetime may facilitate their coherent manipulation for quantum computing.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2020-04-15T22:52:38.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "tilted magnetic field",
      "monolayer ws",
      "controlling valley splitting",
      "long valley relaxation time",
      "dark exciton"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "publisher": "IOP"
    },
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}