Structural and Magnetic Phase Transitions near Optimal Superconductivity in BaFe2(As(1-x)Px)2.
/ Authors
D. Hu, Xingye Lu, Wenliang Zhang, Huiqian Luo, Shiliang Li, Peipei Wang, Genfu Chen, F. Han, Shree R. Banjara, Shree R. Banjara
and 15 more authors
A. Sapkota, A. Sapkota, A. Kreyssig, A. Kreyssig, A. I. Goldman, A. I. Goldman, Z. Yamani, C. Niedermayer, M. Skoulatos, R. Georgii, Thomas Keller, P. Wang, Weiqiang Yu, Pengcheng Dai, Pengcheng Dai
/ Abstract
We use nuclear magnetic resonance (NMR), high-resolution x-ray, and neutron scattering studies to study structural and magnetic phase transitions in phosphorus-doped BaFe2(As(1-x)P(x)2. Previous transport, NMR, specific heat, and magnetic penetration depth measurements have provided compelling evidence for the presence of a quantum critical point (QCP) near optimal superconductivity at x=0.3. However, we show that the tetragonal-to-orthorhombic structural (T{s}) and paramagnetic to antiferromagnetic (AF, TN) transitions in BaFe2(As(1-x)Px)2 are always coupled and approach T{N}≈T{s}≥T{c} (≈29 K) for x=0.29 before vanishing abruptly for x≥0.3. These results suggest that AF order in BaFe_{2}(As(1-x)Px)2 disappears in a weakly first-order fashion near optimal superconductivity, much like the electron-doped iron pnictides with an avoided QCP.
Journal: Physical review letters