Superfluidity in topologically nontrivial flat bands
Loading...
Journal Title
Journal ISSN
Volume Title
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
This publication is imported from Aalto University research portal.
View publication in the Research portal
View/Open full text file from the Research portal
Other link related to publication
View publication in the Research portal
View/Open full text file from the Research portal
Other link related to publication
Author
Date
2015
Department
Major/Subject
Mcode
Degree programme
Language
en
Pages
9
1-9
1-9
Series
NATURE COMMUNICATIONS, Volume 6
Abstract
Topological invariants built from the periodic Bloch functions characterize new phases of matter, such as topological insulators and topological superconductors. The most important topological invariant is the Chern number that explains the quantized conductance of the quantum Hall effect. Here we provide a general result for the superfluid weight Ds of a multiband superconductor that is applicable to topologically nontrivial bands with nonzero Chern number C. We find that the integral over the Brillouin-zone of the quantum metric, an invariant calculated from the Bloch functions, gives the superfluid weight in a flat band, with the bound Dsgreater than or equal to|C|. Thus, even a flat band can carry finite superfluid current, provided the Chern number is nonzero. As an example, we provide Ds for the time-reversal invariant attractive Harper–Hubbard model that can be experimentally tested in ultracold gases. In general, our results establish that a topologically nontrivial flat band is a promising concept for increasing the critical temperature of the superconducting transition.Description
Keywords
Chern number, flat band, multiband superconductors, room-temperature superconductivity, superfluid density, superfluidity, topological invariant
Other note
Citation
Peotta, S & Törmä, P 2015, ' Superfluidity in topologically nontrivial flat bands ', Nature Communications, vol. 6, 8944, pp. 1-9 . https://doi.org/10.1038/ncomms9944
