Oliva-Leyva M, Barrios-Vargas J E, Wang Chumin
Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México, Apartado Postal 70-360, 04510 Mexico City, Mexico.
J Phys Condens Matter. 2018 Feb 28;30(8):085702. doi: 10.1088/1361-648X/aaa7b3.
Nonuniform strain in graphene induces a position dependence of the Fermi velocity, as recently demonstrated by scanning tunnelling spectroscopy experiments. In this work, we study the effects of a position-dependent Fermi velocity on the local density of states (LDOS) of strained graphene, with and without the presence of a uniform magnetic field. The variation of LDOS obtained from tight-binding calculations is successfully explained by analytical expressions derived within the Dirac approach. These expressions also rectify a rough Fermi velocity substitution used in the literature that neglects the strain-induced anisotropy. The reported analytical results could be useful for understanding the nonuniform strain effects on scanning tunnelling spectra of graphene, as well as when it is exposed to an external magnetic field.
正如最近扫描隧道光谱实验所表明的那样，石墨烯中的非均匀应变会引起费米速度的位置依赖性。在这项工作中，我们研究了位置依赖的费米速度对应变石墨烯的局域态密度（LDOS）的影响，有无均匀磁场的情况均在考虑范围内。通过狄拉克方法推导得到的解析表达式成功解释了从紧束缚计算中获得的LDOS变化。这些表达式还纠正了文献中使用的一种粗略的费米速度替代方法，该方法忽略了应变诱导的各向异性。所报道的解析结果对于理解非均匀应变对石墨烯扫描隧道光谱的影响以及石墨烯暴露于外部磁场时的情况可能会有所帮助。
