In this paper, we first study the existence of ground state solutions
for the following Schrödinger systems { − ∆ u + V ∞ u = G u ( u , v ) ,
x ∈ R N , − ∆ v + V ∞ v = G v ( u , v ) , x ∈ R N , u , v >
0 , u , v ∈ H 1 ( R N ) , where N≥3 and G ∈ C 2 ( ( R + ) 2 , R )
. And then, by using variational method and projections on Nehari-Poho z
̆ aev type manifold, we will prove the nonexistence of ground state
solutions for the coupled Schrödinger systems { − ∆ u + V ( x ) u = G u
( u , v ) , x ∈ R N , − ∆ v + V ( x ) v = G v ( u , v ) , x ∈ R N , u ,
v > 0 , u , v ∈ H 1 ( R N ) .