Electronic properties of extended graphene nanomaterials from GW calculations
Electronic properties of extended graphene nanomaterials from GW calculations
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DOI：
10.1002/pssb.200982339
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发表时间：
2009-12
期刊：
影响因子：
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通讯作者：
S. Taioli;P. Umari;M. M. Souza-M.
中科院分区：
文献类型：
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作者：
S. Taioli;P. Umari;M. M. Souza-M.
提出了一种用于加速第一性原理绿色函数计算的计算方法，描述了模型锯齿形碳纳米管（CNT）和手性边缘石墨烯纳米管的电子性质。该方法利用一个最优基组来表示极化传播算子，在不损失精度的情况下降低了计算成本。电子结构和平衡几何结构得到的赝势实施从头算总能量密度泛函理论。精确的计算，以确定准粒子的激发在碳纳米结构，特别是电子带隙，是在自能GW处理的框架。在伽马点处获得的（7，0）、（8，0）CNT的带隙结果以及对具有边缘不规则性的（4，2）纳米晶的计算表明，这种方法有可能对具有技术兴趣的大型碳基系统和具有局部缺陷的结构进行精确计算，否则难以用传统方法解决。这种方法最近由Umari等人实施[Umari等人，Phys. Rev. B 79，201104（2009）]，可以用作扩展系统中的光谱性质、激发态和光学响应的预测工具。
A description of the electronic properties of model zigzag carbon nanotubes (CNTs) and chiral‐edge graphene nanoribbon using a computational method for accelerating first‐principles Green function calculations is presented. This approach utilizes an optimal basis set for representing the polarization propagator lowering the computational cost without loss of accuracy. The electronic structures and the equilibrium geometries were obtained within the pseudopotential implementation of ab initio total energy density functional theory. Accurate calculations to determine quasiparticle excitations in carbon nanostructures, notably electronic band gap, are performed in the framework of GW treatment of self‐energy. The obtained results on band gaps for (7,0), (8,0) CNTs at Gamma point and calculations on (4,2) nanoribbon with edge irregularities show the potential of this method to perform accurate calculations on large carbon‐based systems of technological interest and structures with localized defects, otherwise difficult to address with conventional approaches. This method, recently implemented by Umari et al. [Umari et al., Phys. Rev. B 79, 201104 (2009)], may be used as a predictive tool of spectral properties, excited states and optical response in extended systems.