SKM 2023 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 16: Poster: Transport

TT 16.11: Poster

Montag, 27. März 2023, 15:00–18:00, P2/OG4

Quantum transport simulation for graphene devices with sawtooth-shaped n-p-n junctions — •Zhe-Bin Hsu and Ming-Hao Liu — Department of Physics, National Cheng Kung University, Tainan 70101, Taiwan

Graphene, a gapless two-dimensional semimetal made of carbon atoms arranged in a honeycomb lattice, is an ideal platform for studying electron optics both experimentally and theoretically. Because of its lack of energy gap, n- and p-type carriers in graphene can be easily tuned simply by electrical gating. Typical graphene n-p-n junctions are created by local gates of rectangular shapes that exhibit Fabry-Pérot interference of electron waves in the clean limit. A recent experiment [1] realized a Dirac fermion reflector of graphene using sawtooth-shaped npn junctions, reporting not only the suppressed Fabry-Pérot interference but also resistance enhancement. Motivated by this experiment, we perform quantum transport simulations for graphene considering similar gate and sample geometries. Good consistency between our simulation and the experiment [1] will be shown. Further tests on other shaped top gates are performed in order to find the optimal gate geometry for best enhanced resistance. Our work shows that sawtooth-shaped graphene n-p-n junctions cannot work as a field-effect transistor (FET), even though the transmission can be reduced by a certain amount.

[1] S. Morikawa et al., Semicond. Sci. Technol. 32, 045010 (2017)