We consider the equation \(\begin{aligned} -\Delta u+u=Q_\varepsilon (x)|u|^{p-2}u,\quad u\in H^1(\mathbb {R}^N), \end{aligned}\) where \(Q_\varepsilon \) takes the value 1 on each ball \(B_\varepsilon (y)\) , \(y\in \mathbb {Z}^N\) , and the value \(-1\) elsewhere. We establish the existence of a least energy solution for each \(\varepsilon \in (0,\frac{1}{2})\) and show that their \(H^1\) and \(L^p\) norms concentrate locally at points of \(\mathbb {Z}^N\) as \(\varepsilon \rightarrow 0\) .