# Ising and Spin orders in Iron-Based Superconductors

 Title: Ising and Spin orders in Iron-Based Superconductors Author: Xu, Cenke; Mueller, Markus; Sachdev, Subir Note: Order does not necessarily reflect citation order of authors. Citation: Xu, Cenke, Markus Mueller, and Subir Sachdev. 2008. Ising and spin orders in iron-based superconductors. Physical Review B 78(2): 020501. Full Text & Related Files: 0804.4293v4.pdf (133.9Kb; PDF) Abstract: Motivated by recent neutron scattering experiments, we study the ordering of spins in the iron-based superconductors La(O$$_{1-x}$$F$$_x$$)FeAs, assuming them in proximity to a Mott insulator in the phase diagram. The ground state of the parent system with x = 0 is a spin density wave with ordering wave vector $$\vec{Q}$$ = (0, $$\pi$$) or ($$\pi$$, 0). Upon raising the temperature, we find the system to restore SU(2) symmetry, while an Ising symmetry remains broken, explaining the experimentally observed lattice distortion to a monoclinic crystal structure. Upon further temperature increase, the spins finally disorder at a second transition. The phase transition driven by doping with charge carriers similarly splits into an O(3) transition, and an Ising transition with z = 3 at larger doping. Published Version: doi:10.1103/PhysRevB.78.020501 Other Sources: http://arxiv.org/abs/0804.4293v4 Terms of Use: This article is made available under the terms and conditions applicable to Open Access Policy Articles, as set forth at http://nrs.harvard.edu/urn-3:HUL.InstRepos:dash.current.terms-of-use#OAP Citable link to this page: http://nrs.harvard.edu/urn-3:HUL.InstRepos:7349761 Downloads of this work: