1 research outputs found
Dynamic spin-lattice coupling and nematic fluctuations in NaFeAs
We use inelastic neutron scattering to study acoustic phonons and spin
excitations in single crystals of NaFeAs, a parent compound of iron pnictide
superconductors. NaFeAs exhibits a tetragonal-to-orthorhombic structural
transition at K and a collinear antiferromagnetic (AF) order at
K. While longitudinal and out-of-plane transverse acoustic
phonons behave as expected, the in-plane transverse acoustic phonons reveal
considerable softening on cooling to , and then harden on approaching
before saturating below . In addition, we find that spin-spin
correlation lengths of low-energy magnetic excitations within the FeAs layer
and along the -axis increase dramatically below , and show weak anomaly
across . These results suggest that the electronic nematic phase present
in the paramagnetic tetragonal phase is closely associated with dynamic
spin-lattice coupling, possibly arising from the one-phonon-two-magnon
mechanism