Antiferromagnetic spin excitations in single crystals of nonsuperconducting Li 1 − x FeAs

作者：Meng Wang, Xiaocong Wang, D. L. Abernathy, Leland Harriger, Huiqian Luo, Yang Zhao, J. W. Lynn, Q.Q. Liu, Changqing Jin, Chen Fang, Jiangping Hu, Pengcheng Dai · 发表于：Physical Review B · 年份：2011 · DOI：10.1103/physrevb.83.220515 · 被引用次数：31 · 研究领域：Iron-based superconductors research、Superconductivity in MgB2 and Alloys、Physics of Superconductivity and Magnetism

We use neutron scattering to determine spin excitations in single crystals of nonsuperconducting Li${}_{1\ensuremath{-}x}$FeAs throughout the Brillouin zone. Although angle resolved photoemission experiments and local density approximation calculations suggest poor Fermi surface nesting conditions for antiferromagnetic (AF) order, spin excitations in Li${}_{1\ensuremath{-}x}$FeAs occur at the AF wave vectors $Q=(1,0)$ at low energies, but move to wave vectors $Q=(\ifmmode\pm\else\textpm\fi{}0.5,\ifmmode\pm\else\textpm\fi{}0.5)$ near the zone boundary with a total magnetic bandwidth comparable to that of BaFe${}_{2}$As${}_{2}$. These results reveal that AF spin excitations still dominate the low-energy physics of these materials and suggest both itinerancy and strong electron-electron correlations are essential to understand the measured magnetic excitations.