Flat bands in 2D materials

Date: 28 May 2019

Venue: Campus Groenenborger, Building U, Room 244 - Groeneborgerlaan 171 - 2020 Antwerpen (route: UAntwerpen, Campus Groenenborger)

Time: 4:00 PM - 5:00 PM

Organization / co-organization: CMT

Short description: CMT lecture presented by Dr. Slavisa Milovanovic



Flat bands in 2D materials

Recently, it has been shown that the twisted double-layer graphene exhibits strongly correlated states when the twist angle is set to one of the "magic angles". Discovery of Mott insulator and superconducting phase in these systems [1] triggered enormous interest in twisted van der Waals materials. As it turns out, quantum correlations emerge as a consequence of band flattening [2] due to the appearance of moiré periodicity. In this talk, we will go through the most interesting examples of twisted 2D heterostructures and the exotic phenomena that they harbour. Furthermore, I will talk about other ways to induce band flattening in low-dimensional systems, i.e. by using periodic gauge fields. It has been shown theoretically that flat bands appear in systems with a periodic magnetic field [3]. Recently, researches managed to create a periodic pseudo-magnetic field in buckled graphene [4]. STM measurements revealed a series of peaks that are attributed to the presence of flat bands in this system.

References:

  • [1] Y. Cao et al., Nature 556, 43 (2018). 
  • [2] R. Bistritzer and A. H. MacDonald, PNAS 108, 12233 (2011).
  • [3] M. Tahir and H. Chen, arXiv:1808.10046 (2018).
  • [4] Y. Jiang et al., arXiv:1904.10147 (2019).


Contact email: lucian.covaci@uantwerpen.be

Link: http://cmt.uantwerpen.be