title: Excitonic condensation under spin-orbit coupling and BEC-BCS crossover.
abstract: The condensation of electron-hole pairs is studied at zero temperature and in the presence of a weak spin-orbit coupling (SOC) in coupled quantum wells. Under realistic conditions, a perturbative SOC can have observable effects in the order parameter of the condensate. First, the fermion exchange symmetry is absent. As a result, the condensate spin has no definite parity. Additionally, the excitonic SOC breaks the rotational symmetry yielding a complex order parameter in an unconventional way; i.e., the phase pattern of the order parameter is a function of the condensate density. This is manifested through finite off-diagonal components of the static spin susceptibility, suggesting a new experimental method to confirm an excitonic condensate.
authors.affiliation: Department of Physics and National Nanotechnology Research Center, Bilkent University, 06800 Ankara, Turkey.
authors.forename: T
authors.initials: T
authors.lastname: Hakioğlu
authors.forename: Mehmet
authors.initials: M
authors.lastname: Sahin