Charge, spin and pseudospin in graphene
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 2008.
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| Format: | Praca dyplomowa |
| Język: | eng |
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Massachusetts Institute of Technology
2009
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| Hasła przedmiotowe: | |
| Dostęp online: | http://hdl.handle.net/1721.1/45449 |
| _version_ | 1826201578658332672 |
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| author | Abanin, Dmitry A |
| author2 | Leonid S. Levitov. |
| author_facet | Leonid S. Levitov. Abanin, Dmitry A |
| author_sort | Abanin, Dmitry A |
| collection | MIT |
| description | Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 2008. |
| first_indexed | 2024-09-23T11:53:39Z |
| format | Thesis |
| id | mit-1721.1/45449 |
| institution | Massachusetts Institute of Technology |
| language | eng |
| last_indexed | 2024-09-23T11:53:39Z |
| publishDate | 2009 |
| publisher | Massachusetts Institute of Technology |
| record_format | dspace |
| spelling | mit-1721.1/454492019-04-12T21:30:16Z Charge, spin and pseudospin in graphene Abanin, Dmitry A Leonid S. Levitov. Massachusetts Institute of Technology. Dept. of Physics. Massachusetts Institute of Technology. Dept. of Physics. Physics. Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 2008. Includes bibliographical references (p. 167-180). Graphene, a one-atom-thick form of carbon, has emerged in the last few years as a fertile electron system, highly promising for both fundamental research and applications. In this thesis we consider several topics in electronic and spin properties of graphene, with a particular emphasis on the quantum Hall effect (QHE) regime, where this material exhibits most interesting behavior. We shall start with analyzing general properties of the two-terminal conductance for graphene mono- and bilayer samples. Using conformal invariance and the theory of conformal mappings, we characterize the dependence of conductance on the sample shape. We identify the features which distinguish monolayers and bilayers and illustrate the use of the two-terminal conductance as a tool for sample diagnostic. Next, we present a microscopic study of the edge states in the QHE regime. This analysis provides a simple and general explanation of the half-integer Hall quantization in graphene. We discuss the edge states dispersion for different orientations of the boundary, and propose a way to image the edge states using STM spectroscopy. Then, we extend the picture of edge states to describe QHE in spatially nonuniform systems, recently demonstrated p-n and p-n-p devices. We show that the bipolar p-n and p-n-p junctions can host counter-circulating QHE edge states, which mix at the p-n interfaces, giving rise to fractional and integer quantization of the two-terminal conductance, observed in this structures. Graphene exhibits interesting spin- and valley-polarized QH ferromagnetic (FM) states. We show that spin-polarized QH state at zero doping hosts counter-circulating edge states carrying opposite spins, and propose to use this regime as a vehicle to study spin transport. We study ordering in the valley-polarized QH state. (cont.) Coupling of valley QHFM order parameter to random strain-induced vector potential yields an easy-plane-type ordering of the valley QHFM, giving rise to Berezinskii-Kosterlitz-Thouless transition, with fractionally charged vortices (merons) in the ordered state. by Dmitry A. Abanin. Ph.D. 2009-04-29T17:44:20Z 2009-04-29T17:44:20Z 2008 2008 Thesis http://hdl.handle.net/1721.1/45449 318124571 eng 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. http://dspace.mit.edu/handle/1721.1/7582 180 p. application/pdf Massachusetts Institute of Technology |
| spellingShingle | Physics. Abanin, Dmitry A Charge, spin and pseudospin in graphene |
| title | Charge, spin and pseudospin in graphene |
| title_full | Charge, spin and pseudospin in graphene |
| title_fullStr | Charge, spin and pseudospin in graphene |
| title_full_unstemmed | Charge, spin and pseudospin in graphene |
| title_short | Charge, spin and pseudospin in graphene |
| title_sort | charge spin and pseudospin in graphene |
| topic | Physics. |
| url | http://hdl.handle.net/1721.1/45449 |
| work_keys_str_mv | AT abanindmitrya chargespinandpseudospiningraphene |