We suggest that an inhomogeneous (nonzero-momentum) paired phase can appear in the absence of an external magnetic field in a system with a predominant interband pairing and with separate Fermi-surface sheets. The Fermi wave vector mismatch which appears in such a situation can be compensated by nonzero center-of-mass momentum of the Cooper pairs, which can lead to a spontaneous appearance of the Fulde-Ferrell type of superconducting state. The idea is examined using a tight-binding model which emulates the holelike and the electronlike bands of iron-based superconductors. The state can appear for the cases of both spin-singlet and spin-triplet pairing channels.
number of pulisher's sheets:
0,5
affiliation:
Wydział Fizyki, Astronomii i Informatyki Stosowanej : Instytut Fizyki im. Mariana Smoluchowskiego