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arXiv 1304.0972cond-mat.mtrl-sci
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通过分子电荷转移相互作用调控石墨烯和氮化硼量子点的电子和光学性质

Tuning the Electronic and Optical properties of Graphene and Boron-Nitride Quantum Dots through Molecular Charge-transfer Interactions

Arkamita Bandyopadhyay, Sharma SRKC Yamijala, Swapan K Pati

摘要:

采用自旋极化的第一性原理计算,以四氰基醌二甲烷(TCNQ)和四硫富瓦烯(TTF)为掺杂剂,通过分子电荷转移调控石墨烯(G)和氮化硼(BN)量子点(QD)的电子和光学性质.从我们的计算中,我们发现,掺杂剂和量子点之间的相互作用的性质是类似的掺杂剂和量子点的二维对应部分,即石墨烯和六方氮化硼片之间的相互作用。根据量子点的形成能和量子点与掺杂剂之间的距离,我们发现两种掺杂剂都物理吸附在量子点上。此外,我们发现,GQD强烈的相互作用与掺杂剂相比,BNQDS。有趣的是,虽然掺杂剂被物理吸附在量子点上,但它们的相互作用导致量子点的HOMO-LUMO能隙减小了一半以上。我们还观察到自旋极化HOMO-LUMO间隙在某些量子点掺杂剂复合物。Mulliken布居分析,态密度(DOS),投影DOS(pDOS)图和光学电导率计算已经进行了支持和理解上述发现背后的原因。

英文摘要:

Spin-polarized first-principles calculations have been performed to tune the electronic and optical properties of graphene (G) and boron-nitride (BN) quantum dots (QDs) through molecular charge-transfer using Tetracyanoquinodimethane (TCNQ) and Tetrathiafulvalene (TTF) as dopants. From our calculations, we find that the nature of interaction between the dopants and QDs is similar to the interaction between the dopants and their two-dimensional counter parts of the QDs, namely, graphene and hexagonal boron-nitride sheets. Based on the values of formation energy and distance between QDs and dopants, we find that both the dopants are physisorbed on the QDs. Also, we find that GQDs interact strongly with the dopants compared to the BNQDS. Interestingly, though the dopants are physisorbed on QDs, their interaction lead to a decrement in the HOMO-LUMO gap of QDs by more than half of their original value. We have also observed a spin-polarized HOMO-LUMO gap in certain QD-dopant complexes. Mulliken population analysis, Density of states (DOS), projected DOS (pDOS) plots and optical conductivity calculations have been performed to support and understand the reasons behind the above mentioned findings.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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