Novel properties of frustrated low dimensional magnets with pentagonal symmetry

Anu Jagannathan (1) , Benjamin Motz (2) , Elena Vedmedenko (3)

1 LPS - Laboratoire de Physique des Solides
2 Physics
3 Department of Physics [Hamburg]

In the context of magnetism, frustration arises when a group of spins cannot find a configuration that minimizes all of their pairwise interactions simultaneously. The simplest example is that of a triangle in which the three corners are occupied by Ising spins, and where each pair is coupled antiferromagnetically. We consider a new type of frustrated spin networks with pentagonal loops and long range quasiperiodic structural order. Five-fold loops can be expected to occur naturally in quasicrystals, and experimental studies of icosahedral alloys show manifestations of local five-fold symmetry in a variety of different physical contexts. Our model considers classical spins placed on vertices of a subtiling of the two dimensional Penrose tiling, and interacting with nearest neighbors via antiferromagnetic bonds. The ground state of this system has a complex magnetic structure, and is studied analytically by a recursive method, as well by Monte Carlo simulation on finite clusters. We discuss ground state configurations, the energy, the degeneracy, and the nature of excitations around the ground state.

Mots clés: Physical Sciences

Domaines: Matière Condensée [cond-mat]

Anu Jagannathan, Benjamin Motz, Elena Vedmedenko. Novel properties of frustrated low dimensional magnets with pentagonal symmetry. Philosophical Magazine, 2011, pp.1. ⟨10.1080/14786435.2010.539578⟩. ⟨hal-00665443⟩