Electronic transport in low-angle twisted bilayer graphene

Graphene is a two-dimensional material with exotic electronic, optical and mechanical properties. By stacking two layers of graphene together with a small rotation angle between them, a superlattice of arbitrarily large size can be formed. The hybridization of the electronic states in the two layers can result in reduced Fermi velocity, van Hove singularities and a gapped band structure. In this work, a novel tear-and-stack technique is developed to reliably produce twisted bilayer graphene with controlled angle, and electronic transport measurements of the resulting high-quality samples are performed and discussed. We discover novel insulating states that purely results from the moiŕe superlattice band structure. The magnetotransport properties of these insulating states are studied and indicate that these states have different structure with those in either graphene or AB-stacked bilayer graphene; it shows a non-monotonous change of Fermi surface area which agrees with theoretical calculations. The results point toward a new pathway for graphene-related physics and material research.

Department dc:contributor.department

Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2016

Author dc:creator

• Cao, Yuan, Ph. D. Massachusetts Institute of Technology

Advisor dc:contributor.advisor

• Pablo Jarillo-Herrero.

• Electrical Engineering and Computer Science.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/105685

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/105685