Maamoon Mohamed R, Khalaf A M, Kotb M, Sadeq M S, Kher-Elden Mohammad A, Piquero-Zulaica Ignacio, El-Fattah Zakaria M Abd
Physics Department, Faculty of Science, Al-Azhar University, Nasr City, Cairo, 11884, Egypt.
Basic Science Department, Faculty of Engineering, Sinai University-Kantara Branch, Ismailia, 41636, Egypt.
Sci Rep. 2025 Jun 1;15(1):19218. doi: 10.1038/s41598-025-03707-z.
Edge corrugated, notched graphene nanoribbons (GNRs) exhibit intriguing electronic properties distinct from their straight counterparts, thereby offering suitable candidates for the exploration of electron transport in future carbon-based nanoelectronic devices. Here, we utilize the tight binding (TB) method to investigate the electronic structure and quantum transport in gulf- and chevron-type notched GNRs. Consistent with earlier TB calculations, we reaffirm that the third-nearest neighbour hopping parameter is responsible for the electronic braiding effect and zero-energy conductance channels in straight zigzag GNRs (ZGNRs), here demonstrated for 2ZGNR and 5ZGNR. However, for notched gulf- or chevron-type GNRs, generated by selectively eliminating carbon atoms at either one or both ZGNR edges, the electronic band structures can be radically changed from semiconductor to metallic, with near-Fermi dispersive or flat bands. For the explored asymmetrically notched chevron-type GNRs hosting a metallic flat band at the Fermi energy, unlike straight ZGNRs, the electronic transport was found to depend primarily on the second-nearest neighbour, exhibiting a sharp conductance peak (of 1 unit conductance) at the Fermi energy. This result is found to be generic for all asymmetric chevron-type GNRs, irrespective of the nanoribbon width, and also for edge-notched armchair GNRs hosting similarly metallic flat bands. For the metallic symmetrically notched chevron-type GNR, however, the near-Fermi dispersive bands lead to multiple conductance channels around the Fermi energy, with fine structure dependence on the number of hopping parameters utilized. These results are analyzed with respect to the spatial distribution of the metallic states and how they transverse across the ZGNR leads. The present study should have large implications on the exploration of electronic transport in carbon-based nanoelectronic devices.
边缘呈波纹状、有缺口的石墨烯纳米带（GNRs）展现出与其直边对应物不同的有趣电子特性，从而为未来碳基纳米电子器件中电子输运的探索提供了合适的候选材料。在此，我们利用紧束缚（TB）方法来研究海湾型和人字形缺口GNRs的电子结构和量子输运。与早期的TB计算一致，我们再次确认第三近邻跳跃参数对直边锯齿形GNRs（ZGNRs）中的电子编织效应和零能电导通道负责，这里以2ZGNR和5ZGNR为例进行了证明。然而，对于通过选择性地去除一个或两个ZGNR边缘的碳原子而产生的有缺口的海湾型或人字形GNRs，其电子能带结构可以从半导体彻底转变为金属，具有近费米色散或平带。对于在费米能量处具有金属平带的探索性非对称缺口人字形GNRs，与直边ZGNRs不同，发现电子输运主要取决于第二近邻，在费米能量处呈现出尖锐的电导峰（1个单位电导）。结果发现，这一结果对于所有非对称人字形GNRs都是通用的，与纳米带宽度无关，对于同样具有金属平带的边缘有缺口扶手椅型GNRs也是如此。然而，对于金属对称缺口人字形GNR，近费米色散带在费米能量附近导致多个电导通道，其精细结构取决于所使用的跳跃参数的数量。根据金属态的空间分布以及它们如何穿过ZGNR引线对这些结果进行了分析。本研究对碳基纳米电子器件中电子输运的探索应该具有重大意义。
