Tunable symmetries and Berry’s phase in few layer graphene

There have been extensive studies on monolayer graphene where unique properties result from the symmetry of the honeycomb lattice. Few layer graphene systems are of interest as they offer interesting opportunities to study effect of electronic interactions [1] due to flatter bands while monolayer graphene was largely understood in terms of independent electron picture. In addition, few layer graphene offer an opportunity to break simple symmetries and study their consequence [2]. 

Berry’s phase can be probed using electrical magnetotransport measurements. These measurements can throw up interesting questions in multiband system of few layer graphene.  I will briefly discuss our efforts to measure and understand Berry’s phase in a complex multiband system.

References:

1.  Biswajit Datta, Santanu Dey, Abhisek Samanta, Hitesh Agarwal, Abhinandan Borah, Kenji Watanabe, Takashi Taniguchi, Rajdeep Sensarma, and Mandar M. Deshmukh, Nature Communications 8, 14518 (2017). 
2. Biswajit Datta, Hitesh Agarwal, Abhisek Samanta, Amulya Ratnakar, Kenji Watanabe, Takashi Taniguchi, Rajdeep Sensarma, Mandar M. Deshmukh Physical Review Letters 121, 056801 (2018).