Thursday, August 7, 2014

Findings in Low Dimensional Structures (Surface corrugations influence monolayer graphene electromagnetic response)

By a News Reporter-Staff News Editor at Physics Week -- Current study results on Low Dimensional Structures have been published. 
According to news originating from St. Petersburg, Russia, by VerticalNews correspondents, research stated, "We consider the corrugated monolayer graphene membrane electromagnetic response in terahertz range. We study the generated in irradiated graphene total current (from both valleys) taking into account for the first time both the synthetic electric fields arising due to the (inevitable) presence in graphene of inherent out-of-plane nanodeformations and the double-valleys energy spectrum of Dirac charge particles."

Our news journalists obtained a quote from the research from St. Petersburg State Polytechnic University, "Our approach is based on atomistic quantum mechanics used for the description of (1) the valence pi-sigma. bonds changes generated by activating external periodic electric field and also (2) the mechanism of Dirac electron interaction with this time-dependent perturbation. We consider the problem in the framework of the model of noninteracting Dirac electrons. Assuming surface corrugations not to be very rough we obtain for weak fields the formula for the total current induced in graphene membrane. Our formula describes the curved current paths in the linear in (E) over right arrow (ext) (t) approximation for the given graphene surface form. We show that the local direction of current paths is determined by the synthetic electric field whose direction may essentially differ from the one of the external field and depends on the local curvature of the graphene membrane. We also demonstrate that valley currents generated by a linearly external field have nonzero elliptic polarization angles depending on the point (x,y). Valley currents are shown to rotate in opposite directions in different valleys."

According to the news editors, the research concluded: "The results obtained below can be applied to the analysis of different devices in terahertz optics and optoelectronics and the imaging experiments at the Dirac point."

For more information on this research see: Surface corrugations influence monolayer graphene electromagnetic response. Physica E-Low-Dimensional Systems & Nanostructures, 2014;62():36-42. Physica E-Low-Dimensional Systems & Nanostructures can be contacted at: Elsevier Science Bv, PO Box 211, 1000 AeAmsterdam, Netherlands.

The news correspondents report that additional information may be obtained from Y.A. Firsov, St Petersburg State Polytechnic Univ, St Petersburg 195231, Russia.

Keywords for this news article include: Russia, Eurasia, St. Petersburg, Low Dimensional Structures

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Source: Physics Week

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