  Rotons can exist in ultracold atomic gases either with long-range
interactions or with spin-orbitcoupled dispersions. We find that two different
kinds of rotons coexist in a joint system combining long-range interactions and
spin-orbit coupling. One roton originates from spin-orbit coupling and two
others come from long-range interactions. Their softening can be controlled
separately. The interesting new phenomenon which we find is that
spin-orbit-coupled roton can push down the energy of one long-range-interaction
roton. The spin-orbit coupling accelerates the softening of this roton. The
post phase of spin-orbit-coupling-assisted roton softening and instability is
identified as a superstripe.
