摘要
Antiferromagnetic spin fluctuation is regarded as the leading driving force for electron pairing in high-Tc superconductors.In iron-based superconductors,spin excitations at low energy range,especially the spin-resonance mode at ER~5kBTc,are important for understanding the superconductivity.Here,we use inelastic neutron scattering(INS)to investigate the symmetry and in-plane wave-vector dependence of low-energy spin excitations in uniaxial-strain detwinned Fe Se.The low-energy spin excitations(E<10 meV)appear mainly at Q=(±1,0)in the superconducting state(T9K)and the nematic state(T90 K),confirming the constant C_(2) rotational symmetry and ruling out the C_(4) mode at E≈3 meV reported in a prior INS study.Moreover,our results reveal an isotropic spin resonance in the superconducting state,which is consistent with the s±wave pairing symmetry.At slightly higher energy,low-energy spin excitations become highly anisotropic.The full width at half maximum of spin excitations is elongated along the transverse direction.The Q-space isotropic spin resonance and highly anisotropic low-energy spin excitations could arise from dyz intra-orbital selective Fermi surface nesting between the hole pocket aroundΓpoint and the electron pockets centered at MX point.
作者
刘瑞鲜
Mitsutaka Nakamura
Kazuya Kamazawa
鲁兴业
Ruixian Liu;Mitsutaka Nakamura;Kazuya Kamazawa;Xingye Lu(Center for Advanced Quantum Studies,School of Physics and Astronomy,Beijing Normal University,Beijing 100875,China;J-PARC Center,Japan Atomic Energy Agency(JAEA),Tokai,Ibaraki 319-1195,Japan;Research Center for Neutron Science and Technology,Comprehensive Research Organization for Science and Society,Tokai,Ibaraki 319-1106,Japan)
基金
Beijing Normal University was supported by the Fundamental Research Funds for the Central Universities
the National Key Projects for Research and Development of China(No.2021YFA1400400)
the National Natural Science Foundation of China(Grant Nos.12174029 and 11922402)
the neutron beamtimes from J-PARC(Proposal No.2019A0002)。
作者简介
Corresponding authors:刘瑞鲜.Email:liurx@mail.bnu.edu.cn;Corresponding authors:鲁兴业.Email:luxy@bnu.edu.cn。
