Abstract
In a general Landau-Ginzburg-Wilson Hamiltonian, symmetry allows a term linear in the gradient and trilinear in the order parameter in many cases. General renormalization-group equations to are given for such terms, and applied to the antiferrodistortive phase transition in calcite (). The commensurate transition is continuous in mean-field theory, but in the renormalization-group theory, this new term is relevant near all fixed points to and causes a fluctuation-induced first-order transition.
- Received 30 April 1984
DOI:https://doi.org/10.1103/PhysRevLett.53.2425
©1984 American Physical Society