Structural and Magnetic Phase Transitions near Optimal Superconductivity in BaFe2(As(1-x)Px)2.
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.
Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
Ding
D
Hu
Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
Xingye
X
Lu
Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
Wenliang
W
Zhang
Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
Huiqian
H
Luo
Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.|Collaborative Innovation Center of Quantum Matter, Beijing, China.
Shiliang
S
Li
Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
Peipei
P
Wang
Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
Genfu
G
Chen
Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.
Fei
F
Han
Ames Laboratory, U.S. DOE, Ames, Iowa 50011, USA.|Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA.
Shree R
SR
Banjara
Ames Laboratory, U.S. DOE, Ames, Iowa 50011, USA.|Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA.
A
A
Sapkota
Ames Laboratory, U.S. DOE, Ames, Iowa 50011, USA.|Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA.
A
A
Kreyssig
Ames Laboratory, U.S. DOE, Ames, Iowa 50011, USA.|Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA.
A I
AI
Goldman
Canadian Neutron Beam Centre, National Research Council, Chalk River, Ontario K0J 1P0, Canada.
Z
Z
Yamani
Laboratory for Neutron Scattering, Paul Scherrer Institut, CH-5232 Villigen, Switzerland.
Christof
C
Niedermayer
Laboratory for Neutron Scattering, Paul Scherrer Institut, CH-5232 Villigen, Switzerland.
Markos
M
Skoulatos
Heinz Maier-Leibnitz Zentrum, Technische Universität München, D-85748 Garching, Germany.
Robert
R
Georgii
Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, D-70569 Stuttgart, Germany.|Max Planck Society Outstation at the Forschungsneutronenquelle Heinz Maier-Leibnitz (MLZ), D-85747 Garching, Germany.
T
T
Keller
Department of Physics, Renmin University of China, Beijing 100872, China.
Pengshuai
P
Wang
Department of Physics, Renmin University of China, Beijing 100872, China.
Weiqiang
W
Yu
Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.|Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA.
Pengcheng
P
Dai