Multi-orbital tight binding model for the electronic and optical properties of armchair graphene nanoribbons in the presence of a periodic potential

Nguyen N Hieu; Po-Hsin Shih; Thi-Nga Do; Chuong V Nguyen

doi:10.1088/1361-648X/abdf01

Multi-orbital tight binding model for the electronic and optical properties of armchair graphene nanoribbons in the presence of a periodic potential

J Phys Condens Matter. 2021 Feb 18;33(15). doi: 10.1088/1361-648X/abdf01.

Authors

Nguyen N Hieu^{1

2}, Po-Hsin Shih³, Thi-Nga Do^{4

5}, Chuong V Nguyen⁶

Affiliations

¹ Institute of Research and Development, Duy Tan University, Da Nang 550000, Vietnam.
² Faculty of Natural Sciences, Duy Tan University, Da Nang 550000, Vietnam.
³ Department of Physics, National Cheng Kung University, 701, Taiwan.
⁴ Laboratory of Magnetism and Magnetic Materials, Advanced Institute of Materials Science, Ton Duc Thang University, Ho Chi Minh City, Vietnam.
⁵ Faculty of Applied Sciences, Ton Duc Thang University, Ho Chi Minh City, Vietnam.
⁶ Department of Materials Science and Engineering, Le Quy Don Technical University, Hanoi, Vietnam.

PMID: 33482663
DOI: 10.1088/1361-648X/abdf01

Abstract

The influences of an external electric field with uniform or modulated potential on the electronic and optical properties of armchair graphene nanoribbons (GNRs) are explored using the multi-orbital tight-binding Hamiltonian. The interplay between an electric field and interaction between (s,p_x,p_y,p_z) orbitals remarkably enriches the main features of band structures and absorption spectra. The applied electric field can notably alter the energy dispersions ofπandσbands, leading to the deformation of band-edge states, open and close of a band gap, and modification of the Fermi energy. The vertical optical excitations happen among theπbands, while their available channels depend on the Fermi level which is controlled by theσ-edge bands and a finite potential. With the rich and unique properties, GNRs are suitable candidates for applications in the fields of photodetectors, nanoelectronics, and spintronics. The calculated results are expected to be examined by the angle-resolved photoemission spectroscopies and optical spectroscopies.

Keywords: graphene nanoribbons; modulated potential; optical spectra.