American Physical Society, Physical Review B (Condensed Matter), 14(68), 2003
DOI: 10.1103/physrevb.68.144422
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We study magnetic order in the Heisenberg antiferromagnet on the checkerboard lattice, a two-dimensional version of the pyrochlore network with strong geometric frustration. By employing the semiclassical (1/S) expansion we find that quantum fluctuations of spins induce a long-range order that breaks the four-fold rotational symmetry of the lattice. The ordered phase is a valence-bond crystal. We discuss similarities and differences with the extreme quantum case S = 1/2 and find a useful phenomenology to describe the bond-ordered phases. ; Comment: Minor clarifications + reference to an informal introduction cond-mat/0308091