Manipulating electron waves in graphene using carbon nanotube gating

Alina Mreńca-Kolasińska^1,2, Shiang-Bin Chiu^1*, Ka-Long Lei¹, Ching-Hung Chiu¹, Wun-Hao Kang¹, Szu-Chao Chen¹, Ming-Hao Liu¹

¹Department of Physics, National Cheng Kung University, Tainan, Taiwan
²Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, Kraków, Poland

* Presenter:Shiang-Bin Chiu, email:benrb6602690@gmail.com

Graphene with its dipersion relation resembing that of photons offers ample opportunities for applications in electron optics. Dirac fermions in graphene, being charged, additionally can be manipulated by external electric or magnetic fields. The spacial variation of carrier density by external gates can be used to create few-mode electron waveguides, in analogy to optical fiber, with additional confinement of the carriers in bipolar junctions. We show that waveguides created by gating graphene with carbon nanotubes (CNTs) allow obtaining neatly quantized conductance plateaus, and propose applications in Aharonov-Bohm and two-path interferometers, and point-like source for injection of carriers in graphene. Other application can be extended to Bernal-stacked or twisted bilayer graphene. Thanks to their versatility, CNT-induced waveguides open various possibilities for electron manipulation in graphene-based devices.

Keywords: Graphene, Electron optics, CNT-induced waveguides, Aharonov-Bohm interferometers