Department of Physics, University of California at Berkeley, Berkeley, California 94720, USA.
Nano Lett. 2013 Jan 9;13(1):54-8. doi: 10.1021/nl303426q. Epub 2012 Dec 4.
The sensitive structural dependence of the optical properties of single-walled carbon nanotubes, which are dominated by excitons and tunable by changing diameter and chirality, makes them excellent candidates for optical devices. Because of strong many-electron interaction effects, the detailed dependence of the optical oscillator strength f(s) of excitons on nanotube diameter d, chiral angle θ, and electronic subband index P (the so-called family behavior), however, has been unclear. In this study, based on results from an extended Hubbard Hamiltonian with parameters derived from ab initio GW plus Bethe-Salpeter equation (GW-BSE) calculations, we have obtained an explicit formula for the family behavior of the oscillator strengths of excitons in semiconducting single-walled carbon nanotubes (SWCNTs), incorporating environmental screening. The formula explains recent measurements well and is expected to be useful in the understanding and design of possible SWCNT optical and optoelectronic devices.
单壁碳纳米管的光学性质对结构非常敏感，其光学性质主要由激子决定，通过改变直径和手性即可进行调节，因此它们是光学器件的理想候选材料。由于存在强烈的多电子相互作用，激子的光学振子强度 f(s) 对碳纳米管直径 d、手性角θ和电子子带指数 P 的详细依赖关系（所谓的家族行为）尚不清楚。在这项研究中，我们基于扩展的哈伯德哈密顿量和从头算 GW 加玻恩-辛方程 (GW-BSE) 计算得出的参数，得到了半导体单壁碳纳米管 (SWCNT) 中激子的振子强度家族行为的显式公式，其中包含环境屏蔽。该公式很好地解释了最近的测量结果，有望在理解和设计可能的 SWCNT 光学和光电设备方面发挥作用。
