Spin excitation anisotropy in the paramagnetic tetragonal phase of BaFe2 As2

Yu Li; Weiyi Wang; Yu Song; Haoran Man; Xingye Lu; Frederic Bourdarot; Pengcheng Dai

doi:10.1103/PhysRevB.96.020404

paper

Spin excitation anisotropy in the paramagnetic tetragonal phase of BaFe2 As2

arXiv:1706.08258 · doi:10.1103/PhysRevB.96.020404

Abstract

We use neutron polarization analysis to study temperature dependence of the spin excitation anisotropy in BaFe $_{2}$ As $_{2}$ , which has a tetragonal-to-orthorhombic structural distortion at $T_{s}$ and antiferromagnetic (AF) phase transition at $T_{N}$ with ordered moments along the orthorhombic $a$ -axis below $T_{s} \approx T_{N} \approx 136$ K. In the paramagnetic tetragonal state at 160 K, spin excitations are isotropic in spin space with $M_{a} = M_{b} = M_{c}$ , where $M_{a}$ , $M_{b}$ , and $M_{c}$ are spin excitations polarized along the $a$ , $b$ , and $c$ -axis directions of the orthorhombic lattice, respectively. On cooling towards $T_{N}$ , significant spin excitation anisotropy with $M_{a} > M_{b} \approx M_{c}$ develops below 3 meV with a diverging $M_{a}$ at $T_{N}$ . The in-plane spin excitation anisotropy in the tetragonal phase of BaFe $_{2}$ As $_{2}$ is similar to those seen in the tetragonal phase of its electron and hole-doped superconductors, suggesting that spin excitation anisotropy is a direct probe of doping dependence of spin-orbit coupling and its connection to superconductivity in iron pnictides.

6 pages,4 figures, in press with PRB rapid

Spin excitation anisotropy in the paramagnetic tetragonal phase of BaFe2 As2

Abstract

References in corpus (14)

Cited by in corpus (4)