Ames Laboratory-US DOE, and Department of Physics and Astronomy, Iowa State University, Ames, IA 50011, USA.
J Phys Condens Matter. 2011 Jan 19;23(2):025302. doi: 10.1088/0953-8984/23/2/025302. Epub 2010 Dec 13.
The electronic structure and transport property of a carbon chain between two graphene nanoribbon leads are studied using an ab initio tight-binding (TB) model and Landauer's formalism combined with a non-equilibrium Green's function. The TB Hamiltonian and overlap matrices are extracted from first-principles density functional calculations through the quasi-atomic minimal basis orbital scheme. The accuracy of the TB model is demonstrated by comparing the electronic structure from the TB model with that from first-principles density functional theory. The results of electronic transport on a carbon atomic chain connected to armchair and zigzag graphene ribbon leads, such as different transport characters near the Fermi level and at most one quantized conductance, reveal the effect of the electronic structure of the leads and the scattering from the atomic chain. In addition, bond length alternation and an interesting transmission resonance are observed in the atomic chain connected to zigzag graphene ribbon leads. Our approach provides a promising route to quantitative investigation of both the electronic structure and transport property of large systems.
采用基于第一性原理的紧束缚（TB）模型和非平衡格林函数的 Landauer 公式，研究了连接两个石墨烯纳米带的碳链的电子结构和输运性质。通过准原子最小基轨道方案，从第一性原理密度泛函计算中提取 TB 哈密顿量和重叠矩阵。通过将 TB 模型的电子结构与第一性原理密度泛函理论的电子结构进行比较，验证了 TB 模型的准确性。连接到扶手椅和锯齿形石墨烯带的碳原子链的电子输运结果，如费米能级附近的不同输运特性和最多一个量子电导，揭示了引线电子结构和原子链散射的影响。此外，在连接到锯齿形石墨烯带的原子链中观察到键长交替和有趣的传输共振。我们的方法为定量研究大体系的电子结构和输运性质提供了一条很有前途的途径。
