Theory of biexcitons and biexciton-exciton cascade in graphene quantum dots

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DOIResolve DOI: http://doi.org/10.1103/PhysRevB.91.115314
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TypeArticle
Journal titlePhysical Review B - Condensed Matter and Materials Physics
ISSN1098-0121
Volume91
Issue11
Article number115314
AbstractWe present a microscopic theory of biexcitons in colloidal graphene quantum dots, and we discuss the possibility of a biexciton-exciton cascade generation. Assuming a pz orbital on each carbon atom, the single-particle properties are described in the tight-binding model. The screened direct, exchange, and scattering matrix elements of the Coulomb matrix are calculated using Slater pz orbitals. The many-body ground and excited states are constructed as a linear combination of a finite number of electron-hole pair excitations from the Hartree-Fock ground state by exact diagonalization techniques. The exciton and biexciton states are constructed exploiting the degeneracy of the valence- and conduction-band edges. The two degenerate exciton (X) states and a corresponding biexciton (XX) state are identified for generation of the XX-X cascade in threefold-symmetric quantum dots. Finally, the Auger coupling of the XX state with the excited X states is predicted.
Publication date
PublisherAmerican Physical Society
LanguageEnglish
AffiliationNational Research Council Canada; Security and Disruptive Technologies
Peer reviewedYes
NPARC number21275651
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Record identifierdb12472a-eee4-460d-baf4-7391b2c9f7eb
Record created2015-07-14
Record modified2016-05-09
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