title: Excited Biexcitons in Transition Metal Dichalcogenides.
abstract: The Stochastic Variational Method (SVM) is used to show that the effective mass model correctly estimates the binding energies of excitons and trions but fails to predict the experimental binding energy of the biexciton. Using high-accuracy variational calculations, it is demonstrated that the biexciton binding energy in transition metal dichalcogenides is smaller than the trion binding energy, contradicting experimental findings. It is also shown that the biexciton has bound excited states and that the binding energy of the L = 0 excited state is in very good agreement with experimental data. This excited state corresponds to a hole attached to a negative trion and may be a possible resolution of the discrepancy between theory and experiment.
authors.affiliation: Department of Physics and Astronomy, Vanderbilt University , Nashville, Tennessee 37235, United States.
authors.forename: David K
authors.initials: DK
authors.lastname: Zhang
authors.affiliation: Department of Physics and Astronomy, Vanderbilt University , Nashville, Tennessee 37235, United States.
authors.forename: Daniel W
authors.initials: DW
authors.lastname: Kidd
authors.affiliation: Department of Physics and Astronomy, Vanderbilt University , Nashville, Tennessee 37235, United States.
authors.forename: Kálmán
authors.initials: K
authors.lastname: Varga
mesh_terms: D018011:Chalcogens / Q000737:chemistry*; D028561:Transition Elements / Q000737:chemistry*
chemical_list: D018011:Chalcogens; D028561:Transition Elements
keywords: biexciton; binding energy; excited states; stochastic variational method; transition metal dichalcogenides; two-dimensional materials