Title
Large gap electron-hole superfluidity and shape resonances in coupled graphene nanoribbons Large gap electron-hole superfluidity and shape resonances in coupled graphene nanoribbons
Author
Faculty/Department
Faculty of Sciences. Physics
Publication type
article
Publication
London :Nature Publishing Group ,
Subject
Engineering sciences. Technology
Source (journal)
Scientific reports. - London, 2011, currens
Volume/pages
6(2016) , 9 p.
ISSN
2045-2322
2045-2322
Article Reference
24860
Carrier
E
Target language
English (eng)
Full text (Publishers DOI)
Affiliation
University of Antwerp
Abstract
We predict enhanced electron-hole superfluidity in two coupled electron-hole armchair-edge terminated graphene nanoribbons separated by a thin insulating barrier. In contrast to graphene monolayers, the multiple subbands of the nanoribbons are parabolic at low energy with a gap between the conduction and valence bands, and with lifted valley degeneracy. These properties make screening of the electron-hole interaction much weaker than for coupled electron-hole monolayers, thus boosting the pairing strength and enhancing the superfluid properties. The pairing strength is further boosted by the quasi one-dimensional quantum confinement of the carriers, as well as by the large density of states near the bottom of each subband. The latter magnifies superfluid shape resonances caused by the quantum confinement. Several superfluid partial condensates are present for finite-width nanoribbons with multiple subbands. We find that superfluidity is predominately in the strongly-coupled BEC and BCS-BEC crossover regimes, with large superfluid gaps up to 100 meV and beyond. When the gaps exceed the subband spacing, there is significant mixing of the subbands, a rounding of the shape resonances, and a resulting reduction in the one-dimensional nature of the system.
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Full text (open access)
https://repository.uantwerpen.be/docman/irua/8c2e72/133619.pdf
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