  We review a recent holographic analysis arXiv:1005.4690 of charged black
holes with scalar hair in view of their applications to the cuprate high
temperature superconductors. We show in particular that these black holes show
an interesting phase structure including critical behaviour at zero temperature
or charge, describe both conductors and insulators (including holographic
Mott-like insulators), generically have no residual entropy and exhibit
experimentally observed scaling relations between electronic entropy, specific
heat and (linear) DC resistivity. Transport properties are discussed in the
companion contribution to these proceedings.
