Band structure engineering of graphene by strain: First-principles calculations
Band structure engineering of graphene by strain: First-principles calculations
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通过应变进行石墨烯能带结构工程：第一性原理计算
DOI：
10.1103/physrevb.78.075435
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发表时间：
2008-08-01
影响因子：
3.7
通讯作者：
Zhong, Jianxin
中科院分区：
文献类型：
--
作者：
Gui, Gui;Li, Jin;Zhong, Jianxin
用第一原理赝势平面波方法和紧束缚方法研究了石墨烯在不同平面应变分布下的电子结构。我们发现，具有对称应变分布的石墨烯始终是零禁带半导体，其伪隙在弹性区随应变强度线性减小。然而，石墨烯中不对称的应变分布导致了费米能级的带隙打开。对于应变分布平行于C-C键的石墨烯，当应变增加到12.2%时，其禁带宽度不断增大，达到最大宽度0.486 eV。对于应变垂直于C-C键分布的石墨烯，当应变增加到7.3%时，其禁带宽度不断增加，直到0.170 eV。在不同方向的大应变下，不同泊松比也反映了石墨烯的各向异性。我们发现，在小应变下，泊松比接近于一个常数0.1732，但在大应变下，沿不同方向的泊松比不同程度地减小。
We have investigated the electronic structure of graphene under different planar strain distributions using the first-principles pseudopotential plane-wave method and the tight-binding approach. We found that graphene with a symmetrical strain distribution is always a zero band-gap semiconductor and its pseudogap decreases linearly with the strain strength in the elastic regime. However, asymmetrical strain distributions in graphene result in opening of band gaps at the Fermi level. For the graphene with a strain distribution parallel to C-C bonds, its band gap continuously increases to its maximum width of 0.486 eV as the strain increases up to 12.2%. For the graphene with a strain distribution perpendicular to C-C bonds, its band gap continuously increases only to its maximum width of 0.170 eV as the strain increases up to 7.3%. The anisotropic nature of graphene is also reflected by different Poisson ratios under large strains in different directions. We found that the Poisson ratio approaches to a constant of 0.1732 under small strains but decreases differently under large strains along different directions.