Evaluation of Electronic Coupling in Solids from Ab Initio Periodic Boundary Condition Calculations: The Case of Pentacene Crystal and Bilayer Graphene

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• 作者：Alessandro Biancardi ; Marco Caricato
• 刊名：Journal of Physical Chemistry C
• 出版年：2016
• 出版时间：August 18, 2016
• 年：2016
• 卷：120
• 期：32
• 页码：17939-17948
• 全文大小：628K
• 年卷期：0
• ISSN：1932-7455

文摘

Understanding the modulation of the electronic coupling in molecular crystals and two-dimensional materials is crucial from a fundamental point of view as well as for the development of organic electronics. In this work, we present a first-principles quantum-mechanical method for the calculation of the electronic coupling (or transfer integrals) between fragments or layers, using density functional theory with periodic boundary conditions (DFT-PBC) within the Γ-point approximation. This method is applied to two periodic systems: crystalline pentacene and a bilayer graphene film. For the former system, we find that the inclusion of the solid environment affects the interfragment electronic couplings, with changes of the order of 10%. However, we confirm the qualitative trends obtained with the “isolated molecular dimer” model. For the graphene film, we show how the interlayer coupling changes with the relative position of two π-stacked layers. Interestingly, we find that particle–particle coupling is large even for configurations that are not perfectly stacked.