Novel transport regimes in graphene

Transport phenomena in solids -- such as energy and charge flows in response to external fields -- is a subject of fundamental interest for solid state physics. Carrier transport exhibits a wide variety of intriguing and potentially useful behaviors arising due to a rich and complex interplay between electron-disorder, electron-electron, and electron-phonon interactions. Graphene, a newly discovered carbon one-atom-thick material, has unique transport characteristics, some of which are already well understood, whereas some are being under investigation or are waiting to be discovered. The two-dimensional character and exceptional cleanness of graphene, as well as gate tunability of the carrier density and electron-electron interactions, make graphene an excellent platform to study a range of new transport regimes, such as quantum-coherent ballistic transport, electron hydrodynamics and energy dissipation at the atomic scale. We will study ballistic transport in the context of electronic lensing. We will also demonstrate that electron-electron scattering alters ballistic transport in a dramatic way, giving rise to hole backflows and "memory effects", and leading to experimental signatures such as negative non-local resistance. Upon further increase of the electron-electron interaction strength, the system enters the hydrodynamic regime, where a host of new phenomena can emerge. We also show that the electron-disorder interactions have important implications for energy transport, with energy dissipation occurring predominantly at atomic-scale defects. In this thesis, we will provide a detailed discussion of these topics and their connection to the ongoing experiments.

Department dc:contributor.department

Massachusetts Institute of Technology. Department of Physics.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2018

Author dc:creator

• Kong, Jian Feng

Advisor dc:contributor.advisor

• Leonid Levitov.

• Physics.

Statement dc:rights

• MIT theses are protected by copyright. They may be viewed, downloaded, or printed from this source but further reproduction or distribution in any format is prohibited without written 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/1721.1/119930

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/119930