We present a holographic theory in AdS_4 whose zero temperature ground state
develops a crystal structure, spontaneously breaking translational symmetry.
The crystal is induced by a background magnetic field, but requires no chemical
potential. This lattice arises from the existence of 't Hooft-Polyakov monopole
solitons in the bulk which condense to form a classical object known as a
monopole wall. In the infra-red, the magnetic field is screened and there is an
emergent SU(2) global symmetry.Comment: 33 pages, 16 figures; v2: ref adde
