## Department of Physics Papers

#### Document Type

Journal Article

#### Date of this Version

7-3-2008

#### Abstract

Starting from the irreducible representations of the group of the wave vector, we construct the spin-wave functions consistent with inversion symmetry, neglected in the usual representation analysis. We obtain the relation between the basis functions of different members of the star of the wave vector. We introduce order parameters and determine their transformation properties under the operations of the space group of the paramagnetic crystal. The results are applied to construct terms in the magnetoelectric interaction, which are quadratic and quartic in the magnetic order parameters. The higher-order magnetoelectric interactions can in principle induce components of the spontaneous polarization, which are not allowed by the lowest-order magnetoelectric interaction. We also obtain the relation between the spin-wave functions of the incommensurate phase and those of the commensurate phase, which lead to analogous relations between the order parameters of these two phases.

#### Recommended Citation

Harris, A. B.,
Kenzelmann, M.,
Aharony, A.,
&
Entin-Wohlman, O.
(2008).
Effect of Inversion Symmetry on the Incommensurate Order in Multiferoic *R*Mn_{2}O_{5} (*R* = Rare Earth).
Retrieved from http://repository.upenn.edu/physics_papers/107

**Date Posted:** 25 January 2011

This document has been peer reviewed.

## Comments

Suggested Citation:

A.B. Harris, M. Kenzelmann, A. Aharony and O. Entin-Wohlman. (2008). "Effect of inversion symmetry on the incommensurate order in multiferroic

RMn_{2}O_{5}(R= Rare Earth)."Physical Review B.78, 014407.