Graphene  Vol.2 No.2 , April 2013
Appearance of Negative Differential Conductivity in Graphene Nanoribbons at High-Harmonics
Abstract: We theoretically study current dynamics of graphene nanoribbons subject to DC-AC driven fields. We show that graphene exhibits negative differential conductivity (NDC) at high-harmonics. NDC occurs in the neighborhood where a constant electric field is equal to amplitude of ac field. We also observe NDC at both even and odd harmonics and at wave mixing of two commensurate frequencies. The even harmonics are more pronounced than the odd harmonics. A possible use of the present method for generating terahertz frequencies at even harmonics in graphene is suggested.
Cite this paper: M. Rabiu, S. Y. Mensah and S. S. Abukari, "Appearance of Negative Differential Conductivity in Graphene Nanoribbons at High-Harmonics," Graphene, Vol. 2 No. 2, 2013, pp. 61-65. doi: 10.4236/graphene.2013.22009.

[1]   K. S. Novoselov, A. K. Geim, S. V. Morozov, D. Jiang, Y. Zhang, S. V. Dubonos, I. V. Grigorieva and A. A. Firsov, “Electric Field Effect in Atomically Thin Carbon Films,” Science, Vol. 306, No. 5696, 2004, pp. 666-669. doi:10.1126/science.1102896

[2]   K. S. Novoselov, A. K. Geim, S. V. Morozov, D. Jiang, M. I. Katsenelson, I. V. Grigorieva, S. V. Dubonus and A. A. Firsov, “Two-Dimensional Gas of Massless Dirac Fermions in Graphene,” Nature, Vol. 438, No. 7065, 2005, pp. 197-200. doi:10.1038/nature04233

[3]   R. S. Shishir and D. K. Ferry, “Intrinsic Mobility in Graphene,” Journal of Physics: Condensed Matter, Vol. 21, No. 23, 2009, Article ID: 232204. doi:10.1088/0953-8984/21/23/232204

[4]   L. Brey and H. A. Fertig, “Electronic States of Graphene Nanoribbons,” Physical Review B, Vol. 73, No. 23, 2006, Article ID: 235411.

[5]   F. Hipolito, A. H. Chaves, R. M. Ribeiro, M. I. Vasilevskiy, V. M. Pereira and N. M. R. Peres, “Enhanced Optical Dichroism of Graphene Nanoribbons,” Physical Review B, Vol. 86, No. 11, 2012, Article ID: 115430. doi:10.1103/PhysRevB.86.115430

[6]   K. Sasaki, K. Kato, Y. Tokura, K. Oguri and T. Sogawa, “Theory of Optical Transitions in Graphene Nanoribbons,” Physical Review B, Vol. 84, No. 8, 2011, Article ID: 085458. doi:10.1103/PhysRevB.84.085458

[7]   V. Ryzhii, M. Ryzhii and T. Otsiji, “Negative Dynamic Conductivity of Graphene with Optical Pumping,” Journal of Applied Physics, Vol. 101, No. 8, 2007, Article ID: 083114. doi:10.1063/1.2717566

[8]   S. S. Abukari, S. Y. Mensah, K. W. Adu, N. G. Mensah, K. A. Dompreh, A. Twum, C. L. Y. Amuah, M. Amekpewu and M. Rabiu, “Domain Suppression in the Negative Differential Conductivity Region of Carbon Nanotubes by Applied AC Electric Field,” World Journal of Condensed Matter Physics, Vol. 2, No. 4, 2012, pp. 274- 277. doi:10.4236/wjcmp.2012.24045

[9]   V. I. Litvinov and A. Manasson, “A Large-Signal Negative Dynamic Conductivity and High-Harmonic Oscillations in a Superlattice,” Physical Review B, Vol. 70, No. 19, 2004, Article ID: 195323. doi:10.1103/PhysRevB.70.195323

[10]   S. K. Sekwao and J. P. Leburton, “Hot Electron Terahertz Oscillations in Graphene: Crater and Terraces in the Carrier Distribution Function,” Preprint, arXiv:1003.0842v1.

[11]   K. A. Pronin and A. D. Bandrauk, “Coherent Control of Electric Currents in Superlattices and Molecular Wires: Effect of Relaxation,” Physical Review B, Vol. 69, No. 19, 2004, Article ID: 195308. doi:10.1103/PhysRevB.69.195308

[12]   K. Seeger, “High-Frequency-Induced Phase-Dependent DC Current by Bloch Oscillator Non-Ohmicity,” Applied Physics Letters, Vol. 76, No. 1, 2000, pp. 82-84. doi:10.1063/1.125663