Solutions of a Schrödinger–Poisson system with combined nonlinearities

In this paper, we are concerned with the following Schrödinger–Poisson system{−Δu+V(x)u+λϕu=K(x)|u|q−2u+f(x,u),x∈R3,−Δϕ=u2,lim|x|→+∞⁡ϕ(x)=0,x∈R3, where λ>0λ>0 is a parameter, 1