Electron Optics in Ballistic Graphene

DIPC Seminars

Speaker

Dr. Ming-Hao Liu. Institut fuer Theoretische Physik, Universitaet Regensburg, Germany

When

2016/11/25
13:00

Place

Donostia International Physics Center

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Electrons in clean graphene are known to behave like “charged photons”, exhibiting both electronic and optical properties, due to its celebrated energy dispersion linear in momentum, providinig an ideal platform for exploring electron optics. Despite its discovery in 2004, ballistic graphene devices with micron-scale mean free paths became accessible only recently. Reliable quantum transport simulations in the ballistic limit for understanding and predicting high-quality transport experiments have therefore become increasingly demanded nowadays. In the first part of this talk, an overview of our recent progress on simulating a variety of ballistic graphene transport experiments will be given, including Fabry-Pérot interference in single- [1,2] and bilayer graphene [3], conductance oscillation due to snake states [4], and guiding of electrons in a few-mode ballistic graphene channel [5]. Keys to these simulations will be briefly introduced. In the second part of the talk, our recent proposal for creating and manipulating electron beams in graphene [6] will be illustrated. The proposed lens composed of a parabolic pn junction and a point-like source shows unprecedented control over the electron propagation in ballistic graphene, and will possibly bring the field of electron optics one step forward. [1] Rickhaus, P. et al., Nat. Commun. 4 (2013) 2342. [2] Drienovsky, M. et al., Phys. Rev. B 89 (2014) 115421. [3] Varlet, A. et al., Phys. Rev. Lett. 113 (2014) 116601. [4] Rickhaus, P. et al., Nat. Commun. 6 (2015) 6470. [5] Rickhaus, P. et al., Nano Letters 15 (2015) 5819. [6] Liu, M.-H., Gorini, C., Richter, K., arXiv:1608.01730.