Title: [Joint CQSE & NCTS Seminar] Electronic Quantum Transport in Graphene Superlattice
Speaker: Prof. Ming-Hao Liu (Department of Physics, National Cheng Kung University)
Date: Mar. 25, 2022, 14:30-15:30
Place: NCTS Physics Lecture Hall, 4F, Chee-Chun Leung Cosmology Hall, NTU
Online Link: https://nationaltaiwanuniversity-zbh.my.webex.com/nationaltaiwanuniversity-zbh.my/j.php?MTID=m3efd6c4a404b85f1e7a186a89d9b9009

Abstract:
Electrons in graphene behave like massless Dirac fermions due to the close
analogy between its electronic structure that can be well described by the Dirac equation
and the energy dispersion of photons in vacuum governed by the Planck-Einstein
relation. When a spatially periodic potential that varies in a length scale much longer
than the lattice constant of graphene is applied, its conic band structure is strongly
modified, forming the so-called miniband structure in the resulting graphene
superlattice. Depending on the origin of the underlying periodic potential, there are
different types of graphene superlattices, each exhibiting more complicated transport
behaviors than simple graphene. This talk gives an overview of our recent progress on
quantum transport simulations for various types of graphene superlattices, including
hBN/graphene moiré superlattices [1,2], gate-controlled two-dimensional [3] and one-
dimensional [4] superlattices, and twisted graphene layers [5,6]. Most of the reviewed
works are in collaboration with transport experiments.

[1] S.-C. Chen et al., Communications Physics 3, 71 (2020).
[2] R. Kraft et al., Phys. Rev. Lett. 125, 217701 (2020).
[3] R. Huber et al., Nano Lett. 21, 8046 (2020).
[4] W.-H. Kang et al., Phys. Rev. B 102, 195432 (2020).
[5] P. Rickhaus et al., Science Advances 6, no. 11, eaay8409 (2020).
[6] A. Mrenca-Kolasinska et al., 2D Mater. 9, 025013 (2022).

Biography Brief:
Professor Ming-Hao Liu received his MS and PhD in Physics from National
Taiwan University, Taiwan. From 2011 to 2013, he was an Alexander von Humboldt
Postdoctoral Fellow in University of Regensburg, Germany, where he continued his
postdoctoral research until 2016. In 2017, he returned to Taiwan to join the Department
of Physics of National Cheng Kung University as Assistant Professor, and was
promoted to Associate Professor in 2019. In 2021, he was awarded Ta-You Wu
Memorial Award.