Biexciton Binding of Dirac fermions Confined in Colloidal Graphene Quantum Dots

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• 作者：Cheng Sun ; Florian Figge ; Isil Ozfidan ; Marek Korkusinski ; Xin Yan ; Liang-shi Li ; Pawel Hawrylak ; John A. McGuire
• 刊名：Nano Letters
• 出版年：2015
• 出版时间：August 12, 2015
• 年：2015
• 卷：15
• 期：8
• 页码：5472-5476
• 全文大小：330K
• ISSN：1530-6992

文摘

We present transient absorption measurements and microscopic theory of biexciton binding in triangular colloidal graphene quantum dots consisting of 168 sp²-hybridized C atoms. We observe optical transitions from the lowest orbitally dark singlet exciton states to states below the energy of an unbound dark+bright singlet-exciton pair. Through microscopic calculations of the low-energy exciton and biexciton states via tight-binding, Hartree鈥揊ock, and configuration interaction methods, the spectra reveal a biexciton consisting primarily of a dark-bright singlet-pair bound by 鈭?.14 eV.