Abstract-First-principles study of the terahertz third-order nonlinear response of metallic armchair graphene nanoribbons

Yichao Wang and David R. Andersen

https://journals.aps.org/prb/abstract/10.1103/PhysRevB.93.235430

We compute the terahertz third-order nonlinear conductance of metallic armchair graphene nanoribbons using time-dependent perturbation theory. Significant enhancement of the intrinsic third-order conductance over the result for instrinsic 2D single-layer graphene is observed over a wide range of temperatures. We also investigate the nonlinear response of extrinsic metallic acGNR with |EF|≪200meV. We find that the third-order conductance exhibits a strong Fermi level dependence at low temperatures. A third-order critical field strength of between ∼1 and 5kV/m is computed for the Kerr conductance as a function of temperature. For the third-harmonic conductance, the minimum critical field is computed to be ∼5kV/m.

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Abstract-Quantum Size Effects in the Terahertz Nonlinear Response of Metallic Armchair Graphene Nanoribbons

Yichao Wang, David R. Andersen

(Submitted on 30 Mar 2016)

http://arxiv.org/abs/1603.09394

We use time dependent perturbation theory to study quantum size effects on the terahertz nonlinear response of metallic graphene armchair nanoribbons of finite length under an applied electric field. Our work shows that quantization due to the finite length of the nanoribbon, the applied field distribution, and the broadening of the graphene spectrum all play a significant role in the resulting nonlinear conductances. In certain cases, these effects can significantly enhance the nonlinearity over that for infinitely-long metallic armchair graphene nanoribbon.

Abstract-First-principles study of the terahertz third-order nonlinear response of metallic armchair graphene nanoribbons

Yichao Wang, David R. Andersen

(Submitted on 19 Mar 2016)

http://arxiv.org/abs/1603.06027

We compute the terahertz third-order nonlinear conductance of metallic armchair graphene nanoribbons using time-dependent perturbation theory. Significant enhancement of the intrinsic nonlinear third-order conductance over the result for intrinsic 2D single-layer graphene is observed over a wide range of temperatures and sample geometries. We also investigate the nonlinear response of extrinsic metallic acGNR with |Ef| much smaller than 200 meV. We find that the third-order conductance exhibits a strong Fermi level dependence at low temperatures. A third-order critical field strength of between roughly 1 and 5 kV/m is computed for the nonlinear Kerr terms as a function of temperature. For the third-harmonic terms, the minimum critical field is computed to be around 5 kV/m.