|SPEAKER||劉明豪 - Institute of Theoretical Physics, University of Regensburg, Germany|
|TITLE||Quantum transport simulation for ballistic graphene devices|
|ABSTRACT||Graphene, a truly two-dimensional material discovered in 2004, is known to be an ideal platform for testing and studying relativistic quantum mechanics for its unique linear-in-momentum energy band structure. However, many of the predicted intriguing phenomena based on the Dirac model were hidden in previous experiments due to limited sample quality. In 2013, micron-scale phase-coherent lengths in graphene have been experimentally achieved, and real-space quantum transport simulations that take into account the device geometry have since then become a powerful supporting tool for high-quality graphene transport experiments . In this talk, basic theoretical elements for modelling and simulating real graphene devices will be briefly introduced . Concrete examples will be subsequently illustrated, including suspended graphene pn junctions , graphene on substrate with multiple fine topgates , and hBN-encapsulated bilayer graphene pnp junctions , all of which show very good agreement between experiments and my simulations. Fruitful physics covered in these experiments such as Klein and anti-Klein tunneling, Fabry-Perot interference, half-integer quantum Hall effect, and snake states, will be discussed. The talk will be closed by a summary followed by an outlook for current and future research directions.
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