| Records |
| Author |
Covaci, L.; Berciu, M. |
| Title |
Polaron formation in the presence of Rashba spin-orbit coupling: implications for spintronics |
Type |
A1 Journal article |
Year  |
2009 |
Publication |
Physical Review Letters |
Abbreviated Journal |
Phys Rev Lett |
| Volume |
102 |
Issue |
18 |
Pages |
186403 |
| Keywords |
A1 Journal article |
| Abstract |
We study the effects of the Rashba spin-orbit coupling on polaron formation, using a suitable generalization of the momentum average approximation. While previous work on a parabolic band model found that spin-orbit coupling increases the effective mass, we show that the opposite holds for a tight-binding model, unless both the spin-orbit and the electron-phonon couplings are weak. It is thus possible to lower the effective mass of the polaron by increasing the spin-orbit coupling. We also show that when the spin-orbit coupling is large as compared to the phonon energy, the polaron retains only one of the spin-polarized bands in its coherent spectrum. This has major implications for the propagation of spin-polarized currents in such materials, and thus for spintronic applications. |
| Address |
Department of Physics, University of British Columbia, Vancouver, British Columbia, Canada, V6T 1Z1 |
| Corporate Author |
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Thesis |
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| Publisher |
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Place of Publication |
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Editor |
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| Language |
English |
Wos |
000265948600049 |
Publication Date |
2009-05-08 |
| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
0031-9007 |
ISBN |
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Additional Links |
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| Impact Factor |
8.462 |
Times cited |
25 |
Open Access |
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| Notes |
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Approved |
Most recent IF: 8.462; 2009 IF: 7.328 |
| Call Number |
UA @ lucian @ |
Serial |
4434 |
| Permanent link to this record |
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| Author |
Covaci, L.; Berciu, M. |
| Title |
Survival of the Dirac points in rippled graphene |
Type |
A1 Journal article |
| Year |
2008 |
Publication |
Physical Review Letters |
Abbreviated Journal |
Phys Rev Lett |
| Volume |
100 |
Issue |
25 |
Pages |
256405 |
| Keywords |
A1 Journal article; Electron Microscopy for Materials Science (EMAT); |
| Abstract |
We study the effects of the rippling of a graphene sheet on quasiparticle dispersion. This is achieved using a generalization to the honeycomb lattice of the momentum average approximation, which is accurate for all coupling strengths and at all energies. We show that even though the position of the Dirac points may move and the Fermi speed can be renormalized significantly, quasiparticles with very long lifetimes survive near the Dirac points even for very strong couplings. |
| Address |
Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada, V6T 1Z1 |
| Corporate Author |
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Thesis |
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| Publisher |
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Place of Publication |
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Editor |
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| Language |
English |
Wos |
000257230500047 |
Publication Date |
2008-06-26 |
| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
0031-9007 |
ISBN |
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Additional Links |
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| Impact Factor |
8.462 |
Times cited |
15 |
Open Access |
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| Notes |
|
Approved |
Most recent IF: 8.462; 2008 IF: 7.180 |
| Call Number |
UA @ lucian @ |
Serial |
4010 |
| Permanent link to this record |
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| Author |
Covaci, L.; Berciu, M. |
| Title |
Holstein polaron: The effect of coupling to multiple-phonon modes |
Type |
A1 Journal article |
| Year |
2007 |
Publication |
Epl |
Abbreviated Journal |
Epl-Europhys Lett |
| Volume |
80 |
Issue |
6 |
Pages |
67001 |
| Keywords |
A1 Journal article |
| Abstract |
We investigate the effects of coupling to multiple-phonon modes on the properties of a Holstein polaron. To this end, we generalize the Momentum Average approximations MA((0)) and MA((1)) to deal with multiple-phonon modes. As for a single-phonon mode, these approximations are found to be numerically very efficient. They become exact for very weak or very strong couplings, and are highly accurate in the intermediate regimes, e.g. the spectral weights obey exactly the first six, respectively eight, sum rules. Our results show that the effect on ground-state properties is cumulative in nature. As a result, if the effective coupling to one mode is much larger than to all the others, this mode effectively determines the ground-state properties. However, even very weak coupling to a second phonon mode has important non-perturbational effects on the higher-energy spectrum, in particular on the dispersion and the phonon statistics of the polaron band. This has important consequences on the analysis and interpretation of data for real materials. |
| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
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Place of Publication |
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Editor |
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| Language |
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Wos |
000251648300016 |
Publication Date |
2007-11-30 |
| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
0295-5075 |
ISBN |
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Additional Links |
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| Impact Factor |
1.957 |
Times cited |
9 |
Open Access |
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| Notes |
|
Approved |
Most recent IF: 1.957; 2007 IF: 2.206 |
| Call Number |
UA @ lucian @ |
Serial |
4431 |
| Permanent link to this record |
