Alaal Naresh, Medhekar Nikhil, Shukla Alok
IITB-Monash Research Academy, CSE Building 2nd Floor, IIT Bombay, Mumbai 400076, India and Department of Physics, Indian Institute of Technology Bombay, Mumbai 400076, India.
Department of Materials Engineering, Monash University, Clayton, Victoria 3800, Australia.
Phys Chem Chem Phys. 2018 Apr 18;20(15):10345-10358. doi: 10.1039/c7cp08234g.
We employ a first-principles calculations based density-functional-theory (DFT) approach to study the electronic properties of partially and fully edge-hydrogenated armchair boron-nitrogen-carbon (BNC) nanoribbons (ABNCNRs), with widths between 0.85 nm to 2.3 nm. Due to the partial passivation of edges, the electrons, which do not participate in the bonding, form new energy states located near the Fermi-level. Because of these additional bands, some ABNCNRs exhibit metallic behavior, which is quite uncommon in armchair nanoribbons. Our calculations reveal that metallic behavior is observed for the following passivation patterns: (i) when the B atom from one edge and the N atom from another edge are unpassivated. (ii) when the N atoms from both the edges are unpassivated. (iii) when the C atom from one edge and the N atom from another edge are unpassivated. Furthermore, spin-polarization is also observed for certain passivation schemes, which is also quite uncommon for armchair nanoribbons. Thus, our results suggest that the ABNCNRs exhibit a wide range of electronic and magnetic properties in that the fully edge-hydrogenated ABNCNRs are direct band gap semiconductors, while the partially edge-hydrogenated ones are either semiconducting, or metallic, while simultaneously exhibiting spin polarization, based on the nature of passivation. We also find that the ribbons with larger widths are more stable as compared to the narrower ones.
我们采用基于第一性原理计算的密度泛函理论（DFT）方法，来研究宽度在0.85纳米至2.3纳米之间的部分边缘氢化和完全边缘氢化的扶手椅型硼氮碳（BNC）纳米带（ABNCNRs）的电子性质。由于边缘的部分钝化，不参与成键的电子形成了位于费米能级附近的新能态。由于这些额外的能带，一些ABNCNRs表现出金属行为，这在扶手椅型纳米带中是相当罕见的。我们的计算表明，在以下钝化模式下观察到金属行为：（i）当一条边缘的B原子和另一条边缘的N原子未被钝化时。（ii）当两条边缘的N原子都未被钝化时。（iii）当一条边缘的C原子和另一条边缘的N原子未被钝化时。此外，对于某些钝化方案还观察到了自旋极化，这在扶手椅型纳米带中也很罕见。因此，我们的结果表明，ABNCNRs表现出广泛的电子和磁性性质，即完全边缘氢化的ABNCNRs是直接带隙半导体，而部分边缘氢化的ABNCNRs根据钝化性质要么是半导体，要么是金属，同时还表现出自旋极化。我们还发现，与较窄的纳米带相比，较宽的纳米带更稳定。
