Regensburg 2019 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 14: Graphene
TT 14.7: Vortrag
Montag, 1. April 2019, 16:30–16:45, H22
Current splitter and valley polarizer in elastically deformed graphene — •Nikodem Szpak1 and Thomas Stegmann2 — 1Fakultät für Physik, Universität Duisburg-Essen — 2Instituto de Ciencias Fisicas, UNAM, Mexico
Elastic deformations of graphene can significantly change the
flow paths and valley polarization of the electric currents.
We investigate these phenomena in graphene nanoribbons with localized out-of-plane deformations by means of tight-binding transport calculations. Such deformations can split
the current into two beams of almost completely valley polarized electrons and give rise to a valley voltage. These properties are observed for a fairly wide set of experimentally accessible parameters.
We propose a valleytronic nanodevice in which a high polarization of the electrons comes along with a high transmission making the device very efficient.
In order to gain a better understanding of these effects, we also treat the system in the continuum limit in which the electronic excitations can be described by the Dirac equation coupled to curvature and a pseudo-magnetic field.
Semiclassical trajectories offer then an additional insight into the balance of forces acting on the ballistic electrons and provide a convenient tool for predicting the behavior of the current flow paths.
The proposed device can also be used for a sensitive measurement of graphene deformations.
T. Stegmann and N. Szpak, New J. Phys. 18 (2016) 053016
T. Stegmann and N. Szpak, 2D Materials 2D Materials 6 (2019) 015024