  We investigate the holographic entanglement entropy (HEE) of a strip geometry
in four dimensional Q-lattice backgrounds, which exhibit metal-insulator
transitions in the dual field theory. Remarkably, we find that the HEE always
displays a peak in the vicinity of the quantum critical points. Our model
provides the first direct evidence that the HEE can be used to characterize the
quantum phase transition (QPT). We also conjecture that the maximization
behavior of HEE at quantum critical points would be universal in general
holographic models.
