Abstract Recently, He et al. succeeded in covalently linking porphines to graphene edges on a Ag(111) substrate by dehydrogenative coupling [Nat. Chem. 9 (1) (2017) 33–38], thus created a new hybrid material with tunable functionalities. Motivated by this work, we further investigate the electron transport properties of three porphine/graphene coupling motifs observed by scanning-probe technology with submolecular resolution in the experiment. By using density-functional theory combined with the Keldysh nonequilibrium Green's technique, we find many interesting electron transport phenomena in these new hybrid structures. Conductivity enhancement can be observed when porphines are covalently bound to the edges of specific armchair graphene nanoribbon (AGNR) and symmetric zigzag GNR (ZGNR). However, the origin of conductivity enhancement in the AGNR related hybrid system is completely different from that in the ZGNR related system. Moreover, negative differential resistance (NDR) behaviors can be found in ZGNR related coupling configurations. In particular, two different NDR mechanisms are found in these hybrid systems.

中文翻译：

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卟啉与石墨烯边缘的共价偶联：量子传输特性及其在电子学中的应用

摘要 最近，He 等人。通过脱氢偶联成功地将卟吩共价连接到 Ag(111) 衬底上的石墨烯边缘 [Nat. 化学 9 (1) (2017) 33-38]，从而创造了一种具有可调功能的新型混合材料。受这项工作的启发，我们进一步研究了在实验中通过具有亚分子分辨率的扫描探针技术观察到的三个卟吩/石墨烯偶联基序的电子传输特性。通过使用密度泛函理论结合 Keldysh 非平衡格林技术，我们在这些新的混合结构中发现了许多有趣的电子传输现象。当卟啉与特定扶手椅石墨烯纳米带 (AGNR) 和对称锯齿形 GNR (ZGNR) 的边缘共价结合时，可以观察到导电性增强。然而，AGNR相关混合系统中电导率增强的起源与ZGNR相关系统中的完全不同。此外，负微分电阻 (NDR) 行为可以在 ZGNR 相关耦合配置中找到。特别是，在这些混合系统中发现了两种不同的 NDR 机制。