Asymmetric solitons and domain walls supported by inhomogeneous   defocusing nonlinearity
  We show that an inhomogeneous defocusing nonlinearity that grows toward the periphery in the positive and negative transverse directions at different rates can support strongly asymmetric fundamental and multipole bright solitons, which are stable in wide parameter regions. In the limiting case when nonlinearity is uniform in one direction, solitons transform into stable domain walls (fronts), with constant or oscillating intensity in the homogeneous region, attached to a tail rapidly decaying in the direction of growing nonlinearity. 
Yaroslav V. Kartashov, Valery E. Lobanov, Boris A. Malomed, Lluis   Torner
physics.optics nlin.PS