Issue |
EPL
Volume 115, Number 2, July 2016
|
|
---|---|---|
Article Number | 27008 | |
Number of page(s) | 6 | |
Section | Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties | |
DOI | https://doi.org/10.1209/0295-5075/115/27008 | |
Published online | 30 August 2016 |
Possible singlet and triplet superconductivity on honeycomb lattice
1 National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University Nanjing 210093, China
2 Collaborative Innovation Center of Advanced Microstructures, Nanjing University - Nanjing 210093, China
3 Department of Physics and Institute of Theoretical Physics, Nanjing Normal University - Nanjing, 210023, China
(a) slyu@nju.edu.cn
(b) zj@minus4.org
(c) jxli@nju.edu.cn
Received: 13 May 2016
Accepted: 2 August 2016
We study the possible superconducting pairing symmetry mediated by spin and charge fluctuations on the honeycomb lattice using the extended Hubbard model and the random-phase-approximation method. From 2% to 20% doping levels, a spin-singlet -wave is shown to be the leading superconducting pairing symmetry when only the on-site Coulomb interaction U is considered, with the gap function being a mixture of the nearest-neighbor and next-nearest-neighbor pairings. When the offset of the energy level between the two sublattices exceeds a critical value, the most favorable pairing is a spin-triplet f-wave which is mainly composed of the next-nearest-neighbor pairing. We show that the next-nearest-neighbor Coulomb interaction V is also in favor of the spin-triplet f-wave pairing.
PACS: 74.20.Rp – Pairing symmetries (other than s-wave) / 74.20.Mn – Nonconventional mechanisms / 71.10.Fd – Lattice fermion models (Hubbard model, etc.)
© EPLA, 2016
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