{
  "id": "1312.2918",
  "version": "v2",
  "published": "2013-12-10T19:25:17.000Z",
  "updated": "2015-09-03T19:51:01.000Z",
  "title": "Intervalley biexcitons and many-body effects in monolayer MoS2",
  "authors": [
    "Edbert J. Sie",
    "Alex J. Frenzel",
    "Yi-Hsien Lee",
    "Jing Kong",
    "Nuh Gedik"
  ],
  "comment": "Accepted in Physical Review B",
  "categories": [
    "cond-mat.mes-hall",
    "cond-mat.mtrl-sci"
  ],
  "abstract": "Interactions between two excitons can result in the formation of bound quasiparticles, known as biexcitons. Their properties are determined by the constituent excitons, with orbital and spin states resembling those of atoms. Monolayer transition metal dichalcogenides (TMDs) present a unique system where excitons acquire a new degree of freedom, the valley pseudospin, from which a novel intervalley biexciton can be created. These biexcitons comprise two excitons from different valleys, which are distinct from biexcitons in conventional semiconductors and have no direct analogue in atomic and molecular systems. However, their valley properties are not accessible to traditional transport and optical measurements. Here, we report the observation of intervalley biexcitons in the monolayer TMD MoS2 using ultrafast pump-probe spectroscopy. By applying broadband probe pulses with different helicities, we identify two species of intervalley biexcitons with large binding energies of 60 meV and 40 meV. In addition, we also reveal effects beyond biexcitonic pairwise interactions in which the exciton energy redshifts at increasing exciton densities, indicating the presence of many-body interactions among them.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2013-12-10T19:25:17.000Z",
      "title": "Biexciton formation in monolayer MoS2 observed by transient absorption spectroscopy",
      "abstract": "We report the observation of biexcitons (AA) and heterobiexcitons (AB) in monolayer MoS2 measured using transient absorption spectroscopy. The binding energies of these biexcitons were measured to be 35 meV and 60 meV, respectively, rendering high-order electronic correlations stable against disorder and thermal fluctuations above room temperature. Our measurements also reveal the energy distribution of the hot exciton gas during the cooling process, with cooling times of 1-2 ps. These results suggest the possibility of using biexcitons in monolayer MoS2 for room temperature excitonics applications.",
      "comment": "5 pages, 4 figures",
      "journal": null,
      "doi": null,
      "authors": [
        "Edbert J. Sie",
        "Yi-Hsien Lee",
        "Alex J. Frenzel",
        "Jing Kong",
        "Nuh Gedik"
      ]
    },
    {
      "version": "v2",
      "updated": "2015-09-03T19:51:01.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "monolayer mos2",
      "many-body effects",
      "monolayer transition metal dichalcogenides",
      "applying broadband probe pulses",
      "novel intervalley biexciton"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "adsabs": "2013arXiv1312.2918S"
    }
  }
}