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Abstract
 

Graphene is one of the most popular 2-dimentional material in the last decades. Its excellent electronic properties helped physicists realize many interesting experiments. One interesting phenomenon is the Klein tunneling effect, in which electron can tunnel through a very high barrier without experiencing an exponentially decay [1]. By applying p-n junctions on graphene, Klein tunneling effect is realized and detected by many physicists [2]. According to their results, such as negative reflection [3] and electron confinement in a circular p-n junction [4], shows great potentials of graphene in building electron optics devices. More possibilities of graphene device are still waiting to be discovered. In my proposed device, hexagonal boron nitride (h-BN) are used to encapsulate a periodical-patterned graphene. The patterned graphene functions as a local gate, applying a periodical circular p-n junction to another graphene transferred on the top of the device. Using scanning tunneling microscope (STM) to scan the top layer of graphene, a Moiré pattern is expected to be detected caused by the period difference between graphene lattice and the gate pattern, a modified band structure is expected to be detected by scanning tunneling spectroscopy (STS).

References:
[1] Klein, O. (1929). Die Reflexion von Elektronen an einem Potentialsprung nach der relativistischen Dynamik von Dirac. Zeitschrift für Physik, 53(3-4), 157-165.
[2] Young, A. F., & Kim, P. (2009). Quantum interference and Klein tunneling in graphene heterojunctions. Nature Physics, 5(3), 222.
[3] Lee, G. H., Park, G. H., & Lee, H. J. (2015). Observation of negative refraction of Dirac fermions in graphene. Nature Physics, 11(11), 925.
[4] Zhao, Y., Wyrick, J., Natterer, F. D., Rodriguez-Nieva, J. F., Lewandowski, C., Watanabe, K., ... & Stroscio, J. A. (2015). Creating and probing electron whispering-gallery modes in graphene. Science, 348(6235), 672-675.

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