Stability and The Existence of Coherent Structure in Demixed State of   Binary BEC
  From a linear stability analysis of the Gross Pitaevskii equation for binary Bose Einstein condensates, it is found that the uniform state becomes unstable to a periodic perturbation of wave number k if k exceeds a critical value kc. However we find that a stationary spatially periodic state does not exist. We show the existence of pulse type solutions, when the pulse structure for one condensate is strongly influenced by the presence of the other condensate. 
Sukla Pal, J. K. Bhattacharjee
cond-mat.quant-gas