Multiple small solutions for some Schrödinger–Poisson systems

In this paper, we study the existence of infinitely many solutions for the following nonlinear Schrödinger–Poisson system {−△u+V(x)u+ϕu=f(x,u),x∈R3,−△ϕ=u2,lim|x|→∞ϕ(x)=0, where the nonlinear term f(x,u)f(x,u) is only locally defined for |u||u| small and satisfies some mild conditions.