Neutron scattering measurements of spatially anisotropic magnetic exchange interactions in semiconducting K0.85 Fe1.54Se2 (TN = 280 K.
We use neutron scattering to study the spin excitations associated with the stripe antiferromagnetic order in semiconducting K(0.85)Fe(1.54)Se(2) (T(N) = 280 K). We show that the spin-wave spectra can be accurately described by an effective Heisenberg Hamiltonian with highly anisotropic inplane couplings at T = 5 K. At high temperature (T = 300 K) above T(N), short-range magnetic correlation with anisotropic correlation lengths are observed. Our results suggest that, despite the dramatic difference in the Fermi surface topology, the inplane anisotropic magnetic couplings are a fundamental property of the iron-based compounds; this implies that their antiferromagnetism may originate from local strong correlation effects rather than weak coupling Fermi surface nesting.
State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China.
Jun
J
Zhao
State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China.
Yao
Y
Shen
Department of Physics, University of California, Berkeley, California 94720, USA and Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA.
R J
RJ
Birgeneau
Department of Physics, Renmin University of China, Beijing 100872, China.
Miao
M
Gao
Department of Physics, Renmin University of China, Beijing 100872, China.
Zhong-Yi
ZY
Lu
Department of Physics, University of California, Berkeley, California 94720, USA and Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
D-H
DH
Lee
State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China.
X Z
XZ
Lu
State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China.
H J
HJ
Xiang
Neutron Scattering Science Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6393, USA.
D L
DL
Abernathy
NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA and Department of Materials Science and Engineering, University of Maryland, College Park, Maryland 20742, USA.
Y
Y
Zhao