Roles of interlayer interactions in stacked 2D crystals

When:
18/07/2019 @ 11:00 AM – 12:00 PM Asia/Singapore Timezone
2019-07-18T11:00:00+08:00
2019-07-18T12:00:00+08:00
Where:
S16 Level 6 – Theory Common Conference Room
Roles of interlayer interactions in stacked 2D crystals @ S16 Level 6 – Theory Common Conference Room

Speaker: Prof Young-Woo Son
Affiliation: Korea Institute for Advanced Study, Seoul, Korea
Host: Asst Prof Vitor Pereira
Location: Click HERE for directions

Abstract Details: Interlayer interactions in stacked 2D crystals are one of key ingredients in exhibiting their qualitative different physical properties [1]. For example, a well-known 2D quantum spin Hall insulating transition metal dichalcogenide can show either topological Weyl metallic phase or trivial one depending on a minute stacking order difference [1,2]. Recent advances in fabricating stacked 2D crystals enable us to perform controlled studies on interesting electronic, magnetic and topological properties in low dimensional heterostructures. In this talk, I will first discuss interplay between interlayer interactions and electronic properties in graphene bilayer systems [3,4]. And I will also briefly discuss a possible modification in its phonon spectrum [5]. Regarding on electronic properties, I will show that the system has a quasicrystalline order through a perfect incommensurate interlayer interaction when two graphene rotate 30 degrees with respect to each other and shows localized 12-fold resonant states with fractal scaling [3,4]. In addition to existing 2D materials, if time allowed, I will also introduce a new computational scheme [6] to search a new family of 2D crystals [7] that will expand both material and property spaces of layered crystals.

References:
[1] Y.-W. Son, Nature 565, 32 (2019).
[2] H.-J. Kim, S.-H. Kang, I. Hamada and Y.-W. Son, PRB 95, 180101 (R) (2017)
[3] S. J. Ahn et al, Science 361, 782 (2018)
[4] P. Moon, M. Koshino, and Y.-W. Son, PRB 99, 165430 (2019)
[5] M. Koshino and Y.-W. Son, arXiv:1905.09660 (2019).
[6] K. Chae, D. Y. Kim, and Y.-W. Son, 2D Mater. 5, 025013 (2018)
[7] K. Chae and Y.-W. Son, Nano Lett. 19, 2694 (2019)

About the Speaker: Prof Young-Woo Son received his Ph. D. Physics at Seoul National University in 2004 and had been a Postdoctor at UC Berkeley till 2006. He was Assistant Professor at Dept. Physics at Konkuk University Seoul Korea in 2007. He is currently a Professor at the Korea Institute for Advanced Study since 2008. He was a Visiting Professor at UC Berkeley in 2014 and a Visiting Professor at the Osaka University in 2017.