Abstract
Theoretically, it has been demonstrated that armchair Graphene nanoribbons (GNRs) can be divided into three families, i.e., , and (here is the number of dimer lines across the ribbon width and is an integer), according to their electronic structures, and the energy gaps for the three families are quite different even with the same . However, a systematic experimental verification of this fundamental prediction is still lacking, owing to very limited atomic-level control of the width of the armchair GNRs investigated. Here, we studied electronic structures of the armchair GNRs with atomically well-defined widths ranging from to by using a scanning tunneling microscope. Our result demonstrated explicitly that all the studied armchair GNRs exhibit semiconducting gaps and, more importantly, the observed gaps as a function of are well grouped into the three categories, as predicted by density-functional theory calculations. Such a result indicated that the electronic properties of the armchair GNRs can be tuned dramatically by simply adding or cutting one carbon dimer line along the ribbon width.
- Received 3 February 2016
- Revised 8 May 2016
DOI:https://doi.org/10.1103/PhysRevB.93.241403
©2016 American Physical Society