E-viri
PDF
Recenzirano
Odprti dostop
-
Lu, Xingye; Park, J. T.; Zhang, Rui; Luo, Huiqian; Nevidomskyy, Andriy H.; Si, Qimiao; Dai, Pengcheng
Science (American Association for the Advancement of Science), 08/2014, Letnik: 345, Številka: 6197Journal Article
Understanding the microscopic origins of electronic phases in high-transition temperature (high-Tc) superconductors is important for elucidating the mechanism of superconductivity. In the paramagnetic tetragonal phase of BaFe2–xTxAs2 (where T is Co or Ni) iron pnictides, an in-plane resistivity anisotropy has been observed. Here, we use inelastic neutron scattering to show that low-energy spin excitations in these materials change from fourfold symmetric to twofold symmetric at temperatures corresponding to the onset of the in-plane resistivity anisotropy. Because resistivity and spin excitation anisotropies both vanish near optimal superconductivity, we conclude that they are likely intimately connected.
