title: Peierls-like transition induced by frustration in a two-dimensional antiferromagnet.
abstract: We show that the introduction of frustration into the spin- 1/2 two-dimensional (2D) antiferromagnetic Heisenberg model on a square lattice via a next-nearest-neighbor exchange interaction can lead to a Peierls-like transition, from a tetragonal to an orthorhombic phase, when the spins are coupled to adiabatic phonons. The two different orthorhombic ground states define an Ising order parameter, which is expected to lead to a finite temperature transition. Implications for Li(2)VOSiO(4), the first realization of that model, will be discussed.
authors.affiliation: Institut de Physique Théorique, Université de Lausanne, CH-1015 Lausanne, Switzerland.
authors.forename: Federico
authors.initials: F
authors.lastname: Becca
authors.forename: Frédéric
authors.initials: F
authors.lastname: Mila