ABSTRACT
The ultimate 2D nature of electron transport and the absence of an energy gap separating conduction and valence bands make graphene layers a unique platform to investigate and engineer various quantum transport phenomena. Here, we will review some of our past and ongoing efforts in the relevant research area by focusing on quantum coherence and correlations effects in graphene nanostructures. First, we will discuss experimental efforts to build various types of ultraclean suspended graphene devices [1-3], where we found the even-denominator fractional quantum-Hall state at an unusual filling factor nu = -1/2 [4] as well as many-body phase transitions in graphene multilayers up to N=8 at charge neutrality point [5-7]. Secondly, we will show that by stacking graphene on semiconducting transition metal dichalcogenides, we can significantly enhance the spin-orbit coupling in graphene [8, 9], which has been of considerable interests in both fundamental and application aspects. Lastly, we will talk about our group’s ongoing efforts to reveal new quantum coherence and correlations effects in graphene and 2D materials.
[1] D.-K. Ki and A. F. Morpurgo, Phys. Rev. Lett. 108, 266601 (2012).
[2] A. L. Grushina, D.-K. Ki, and A. F. Morpurgo, Appl. Phys. Lett. 102, 223102 (2013).
[3] D.-K. Ki and A. F. Morpurgo, Nano Lett. 13, 5165 (2013).
[4] D.-K. Ki, V. I. Fal'ko, D. A. Abanin, and A. F. Morpurgo, Nano Lett. 14, 2135 (2014).
[5] A. L. Grushina, D.-K. Ki, M. Koshino, A. A. L. Nicolet, C. Faugeras, E. McCann, M. Potemski, and A. F. Morpurgo, Nat. Commun. 6, 6419 (2015).
[6] Y. Nam, D.-K. Ki, M. Koshino, E. McCann, and A. F. Morpurgo, 2D Mater. 3, 045014 (2016).
[7] Y. Nam, D.-K. Ki, D. Soler-Delgado, and A. F. Morpurgo, Science 362, 324 (2018).
[8] Z. Wang, D. K. Ki, H. Chen, H. Berger, A. H. MacDonald, and A. F. Morpurgo, Nat. Commun. 6, 8339 (2015).
[9] Z. Wang, D.-K. Ki, J. Y. Khoo, D. Mauro, H. Berger, L. S. Levitov, and A. F. Morpurgo, Phys. Rev. X 6, 041020 (2016).
BIOGRAPHY
Dong-Keun Ki received PhD from POSTECH, Korea in 2010, and is currently appointed as an Assistant Professor in the Department of Physics, The University of Hong Kong (HKU) since 2018. Before joining the HKU, he has worked as a Senior Research Associate in the University of Geneva in Switzerland with Prof. Alberto Morpurgo. He focuses on understanding quantum transport properties of various types of low-dimensional nanostructures, including graphene and 2D materials. He has published several high-impact papers in Nature Physics, Nature Comm., PRL, and Science.
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