Exciton effects in strained armchair graphene nanoribbons

2016 ◽  
Vol 30 (06) ◽  
pp. 1650021 ◽  
Author(s):  
Yonglei Jia ◽  
Junlin Liu
Keyword(s):  
Binding Energy ◽  
Excitation Energy ◽  
Graphene Nanoribbons ◽  
Tight Binding ◽  
Uniaxial Strain ◽  
Exciton Binding Energy ◽  
Coulomb Interactions ◽  
Optomechanical Systems ◽  
Armchair Graphene Nanoribbons ◽  
Armchair Graphene

The exciton effects in 1-nm-wide armchair graphene nanoribbons (AGNRs) under the uniaxial strain were studied within the nonorthogonal tight-binding (TB) model, supplemented by the long-range Coulomb interactions. The obtained results show that both the excitation energy and exciton binding energy are modulated by the uniaxial strain. The variation of these energies depends on the ribbon family. In addition, the results show that the variation of the exciton binding energy is much weaker than the variation of excitation energy. Our results provide new guidance for the design of optomechanical systems based on graphene nanoribbons.

Spin gapless armchair graphene nanoribbons under magnetic field and uniaxial strain

2013 ◽  
Vol 22 (8) ◽  
pp. 087303
Author(s):  
Hai-Ping Hou ◽  
Yue-E Xie ◽  
Yuan-Ping Chen ◽  
Tao Ouyang ◽  
Qing-Xia Ge ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Graphene Nanoribbons ◽  
Uniaxial Strain ◽  
Armchair Graphene Nanoribbons ◽  
Armchair Graphene

scholarly journals Intrinsic Spin-Orbit Coupling in Zigzag and Armchair Graphene Nanoribbons

2011 ◽  
Vol 2011 ◽  
pp. 1-7
Author(s):  
Ying Li ◽  
Erhu Zhang ◽  
Baihua Gong ◽  
Shengli Zhang
Keyword(s):  
Graphene Nanoribbons ◽  
Tight Binding ◽  
Geometrical Parameters ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Binding Model ◽  
Tight Binding Approximation ◽  
Energy Gaps ◽  
Armchair Graphene Nanoribbons ◽  
Armchair Graphene

Starting from a tight-binding model, we derive the energy gaps induced by intrinsic spin-orbit (ISO) coupling in the low-energy band structures of graphene nanoribbons. The armchair graphene nanoribbons may be either semiconducting or metallic, depending on their widths in the absence of ISO interactions. For the metallic ones, the gaps induced by ISO coupling decrease with increasing ribbon widths. For the ISO interactions, we find that zigzag graphene nanoribbons with odd chains still have no band gaps while those with even chains have gaps with a monotonic decreasing dependence on the widths. First-principles calculations have also been carried out, verifying the results of the tight-binding approximation. Our paper reveals that the ISO interaction of graphene nanoribbons is governed by their geometrical parameters.

Electronic properties of armchair graphene nanoribbons under uniaxial strain and electric field

2018 ◽  
Vol 32 (24) ◽  
pp. 1850263 ◽  
Author(s):  
Li-Feng Jiang ◽  
Lei Xu ◽  
Jun Zhang
Keyword(s):  
Electric Field ◽  
Electronic Properties ◽  
Energy Gap ◽  
Graphene Nanoribbons ◽  
Uniaxial Strain ◽  
Quantum Phenomenon ◽  
Suitable Combination ◽  
Armchair Graphene Nanoribbons ◽  
Opening And Closing ◽  
Armchair Graphene

The armchair graphene nanoribbons (AGNRs) can be either semiconducting or metallic, depending on their widths. We investigate the electronic properties of AGNRs under uniaxial strain and electric field. We find that the bulk gap decreases gradually with the increase of the electric field for semiconducting case, but it cannot vanish completely in an appropriate range, which is similar to that of a single uniaxial strain. However, a suitable combination of electric field and uniaxial strain can lead to that the energy gap completely vanishes and reopens. For the metallic case, the bulk gap can display the same opening and closing behavior under an electric field and uniaxial strain. Finally, an interesting quantum phenomenon is obtained by applying a perpendicular magnetic field.

scholarly journals Role Played by Edge-Defects in the Optical Properties of Armchair Graphene Nanoribbons

Nanomaterials ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3229
Author(s):  
Thi-Nga Do ◽  
Godfrey Gumbs ◽  
Danhong Huang ◽  
Bui D. Hoi ◽  
Po-Hsin Shih
Keyword(s):  
Optical Properties ◽  
Graphene Nanoribbons ◽  
Tight Binding ◽  
Edge States ◽  
Binding Model ◽  
Edge Defect ◽  
Flat Bands ◽  
Edge Defects ◽  
Armchair Graphene Nanoribbons ◽  
Armchair Graphene

We explore the implementation of specific optical properties of armchair graphene nanoribbons (AGNRs) through edge-defect manipulation. This technique employs the tight-binding model in conjunction with the calculated absorption spectral function. Modification of the edge states gives rise to the diverse electronic structures with striking changes in the band gap and special flat bands at low energy. The optical-absorption spectra exhibit unique excitation peaks, and they strongly depend on the type and period of the edge extension. Remarkably, there exist the unusual transition channels associated with the flat bands for selected edge-modified systems. We discovered the special rule governing how the edge-defect influences the electronic and optical properties in AGNRs. Our theoretical prediction demonstrates an efficient way to manipulate the optical properties of AGNRs. This might be of importance in the search for suitable materials designed to have possible technology applications in nano-optical, plasmonic and optoelectronic devices.

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