Fulde–Ferrell superfluids in spinless ultracold Fermi gases

Autor: Zhen-Fei Zheng, Guang-Can Guo, Zhen Zheng, Xu-Bo Zou
Jazyk: angličtina
Rok vydání: 2018
Předmět:
Zdroj: New Journal of Physics, Vol 20, Iss 6, p 063001 (2018)
Druh dokumentu: article
ISSN: 1367-2630
DOI: 10.1088/1367-2630/aac7f1
Popis: The Fulde–Ferrell (FF) superfluid phase, in which fermions form finite momentum Cooper pairings, is well studied in spin-singlet superfluids in past decades. Different from previous works that engineer the FF state in spinful cold atoms, we show that the FF state can emerge in spinless Fermi gases confined in optical lattice associated with nearest-neighbor interactions. The mechanism of the spinless FF state relies on the split Fermi surfaces by tuning the chemistry potential, which naturally gives rise to finite momentum Cooper pairings. The phase transition is accompanied by changed Chern numbers, in which, different from the conventional picture, the band gap does not close. By beyond-mean-field calculations, we find the finite momentum pairing is more robust, yielding the system promising for maintaining the FF state at finite temperature. Finally we present the possible realization and detection scheme of the spinless FF state.
Databáze: Directory of Open Access Journals