Least energy sign-changing solutions for a class of fourth order Kirchhoff-type equations in RN

In this article we study the problem Delta(2)u - (a + b integral(RN) vertical bar del u vertical bar(2) dx) Delta u + V(x)u = vertical bar u vertical bar(p-2) u in R-N, where Delta(2) := Delta(Delta) is the biharmonic operator, a, b > 0 are constants, N <= 7, p is an element of (4, 2(*)) for 2(*) defined below, and V(x) is an element of C(R-N, R). Under appropriate assumptions on V( x), the existence of least energy sign-changing solution is obtained by combining the variational methods and the Nehari method.