Ballistic conduction in graphene heterostructures
Abstract/Contents
- Abstract
- Electronic transport in a solid is ballistic unless disturbed by disorder. This work describes experiments on a two-dimensional electron system that resides in the heterostructure formed by graphene and hexagonal boron nitride. The ballistic conduction of electrons is probed across micron length scales by examining the transverse electron focusing effect, in which semiclassical electron trajectories emanating from a point on the system boundary are bent by an applied magnetic field and are focused onto another point. Internal reflection at the boundary extends these trajectories into skipping orbits; the observation and analysis of ballistic conduction that proceeds thus characterizes the interaction of an electron in graphene with the edge. Transverse electron focusing is also exhibited in the 14 nm-period moire superlattice, which is formed by the incommensurability and misalignment between the graphene and boron nitride lattices. At low temperatures, ballistic motion exhibits caustics of skipping orbits extending over hundreds of superlattice periods, reversals of the cyclotron revolution for five successive minibands, and breakdown of cyclotron orbits near van Hove singularities. A theory of nearly free Dirac fermions that obey semiclassical equations of motion successfully describes the system. The interlayer interaction parameter and the full miniband structure can be determined quantitatively. Probing such miniband conduction properties is a necessity for engineering novel transport behaviors in superlattices, and the results suggest possibilities for new device functions and more exotic physics in similar van der Waals heterostructures. A direct point-to-point measurement of ballistic transport also enables quantitative measurement of the effect of the electron-electron interaction on the transport of quasiparticles in a clean two-dimensional Fermi liquid, in particular the crossover from the regime of ballistic transport to the viscous and hydrodynamic flow regime as a function of increasing temperature.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Publication date | 2016 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | Lee, Menyoung |
|---|---|
| Associated with | Stanford University, Department of Physics. |
| Primary advisor | Goldhaber-Gordon, David, 1972- |
| Thesis advisor | Goldhaber-Gordon, David, 1972- |
| Thesis advisor | Kivelson, Steven |
| Thesis advisor | Moler, Kathryn A |
| Advisor | Kivelson, Steven |
| Advisor | Moler, Kathryn A |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Menyoung Lee. |
|---|---|
| Note | Submitted to the Department of Physics. |
| Thesis | Thesis (Ph.D.)--Stanford University, 2016. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2016 by Men Young Lee
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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