Li, SL , Chinese Acad Sci, Inst Phys, Beijing Natl Lab Condensed Matter Phys, Beijing 100190, Peoples R China
部门归属:
[Li, SL; Wang, M; Luo, HQ; Lu, XY; Hu, JP; Xiang, T; Dai, PC] Chinese Acad Sci, Inst Phys, Beijing Natl Lab Condensed Matter Phys, Beijing 100190, Peoples R China; [Zhang, CL; Wang, M; Dai, PC] Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA; [Faulhaber, E; Schneidewind, A] Gemeinsame Forsch Grp HZB TU Dresden, Helmholtz Zentrum Berlin Mat & Energie, D-14109 Berlin, Germany; [Faulhaber, E; Schneidewind, A] TU Mnchen, Forsch Neutronenquelle Heinz Maier Leibnitz FRM 2, D-85747 Garching, Germany; [Hu, JP] Purdue Univ, Dept Phys, W Lafayette, IN 47907 USA; [Xiang, T] Chinese Acad Sci, Inst Theoret Phys, Beijing 100190, Peoples R China; [Dai, PC] Oak Ridge Natl Lab, Neutron Scattering Sci Div, Oak Ridge, TN 37831 USA
英文摘要:
We use cold neutron spectroscopy to study the low-energy spin excitations of superconducting (SC) FeSe(0.4)Te(0.6) and essentially nonsuperconducting (NSC) FeSe(0.45)Te(0.55). In contrast with BaFe(2-x)(Co, Ni)(x)As(2), where the low-energy spin excitations are commensurate both in the SC and normal state, the normal-state spin excitations in SC FeSe(0.4)Te(0.6) are incommensurate and show an hourglass dispersion near the resonance energy. Since similar hourglass dispersion is also found in the NSC FeSe(0.45)Te(0.55), we argue that the observed incommensurate spin excitations in FeSe(1-x)Te(x) are not directly associated with superconductivity. Instead, the results can be understood within a picture of Fermi surface nesting assuming extremely low Fermi velocities and spin-orbital coupling.
