Magnetic ground state of FeSe

• Published in: Nature communications Vol. 7; no. 1; p. 12182
• Main Authors: Wang, Qisi, Shen, Yao, Pan, Bingying, Zhang, Xiaowen, Ikeuchi, K., Iida, K., Christianson, A. D., Walker, H. C., Adroja, D. T., Abdel-Hafiez, M., Chen, Xiaojia, Chareev, D. A., Vasiliev, A. N., Zhao, Jun
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 19-07-2016; Nature Publishing Group; Nature Portfolio
• Subjects: 639/301/119/997; 639/766/119/1003; Energy; Humanities and Social Sciences; multidisciplinary; Neutrons; Physics; Science; Science (multidisciplinary); United States > US; China; Tennessee; Russia
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/ncomms12182

Elucidating the nature of the magnetism of a high-temperature superconductor is crucial for establishing its pairing mechanism. The parent compounds of the cuprate and iron-pnictide superconductors exhibit Néel and stripe magnetic order, respectively. However, FeSe, the structurally simplest iron-based superconductor, shows nematic order (
T
s
=90 K), but not magnetic order in the parent phase, and its magnetic ground state is intensely debated. Here we report inelastic neutron-scattering experiments that reveal both stripe and Néel spin fluctuations over a wide energy range at 110 K. On entering the nematic phase, a substantial amount of spectral weight is transferred from the Néel to the stripe spin fluctuations. Moreover, the total fluctuating magnetic moment of FeSe is ∼60% larger than that in the iron pnictide BaFe
2
As
2
. Our results suggest that FeSe is a novel
S
=1 nematic quantum-disordered paramagnet interpolating between the Néel and stripe magnetic instabilities.
Different ground states of high-temperature superconductors reveal complex nature of magnetism. Here, Wang
et al
. report stripe and Néel spin fluctuations coexisting with non-magnetic nematic phase in FeSe, providing a viewpoint towards understanding the magnetism of cuprate and iron-based superconductors.