论文标题
基于112型铁的超导体CA $ _ {0.82} $ la $ _ {0.18} $ fe $ _ {0.96} $ ni $ _ {0.04} $ as $ _ {2} $
Spin fluctuations in the 112-type iron-based superconductor Ca$_{0.82}$La$_{0.18}$Fe$_{0.96}$Ni$_{0.04}$As$_{2}$
论文作者
论文摘要
我们报告了对基于112型铁的超导体（FESC）Ca $ _ {0.82} $ la $ _ {0.18} $ _ {0.18} $ fe $ _ {0.96} $ ni $ _ {0.096} $ _ {0.044} $ {2 $ _（2 cal）的飞行时间非弹性中子散射（INS）调查（INS）调查。与在室温下在室温下具有中心对称四方晶格结构（空间$ i4/mmm $）的122型FESC和在低温下的平面条纹型防铁磁（AF）订单相比，在低温下，112个系统的系统具有非中心合理结构（太空组$ p2_）以及具有类似波形$ \ mathbf {q} _ {\ mathrm {af}} $的磁接地状态，但是父级化合物中有序矩的不同方向。我们的INS研究清楚地表明，超导CALA-112中的平面内分散体和自旋激发的带宽与122个系统中的旋转兴奋感非常相似。虽然总波动矩$ \ langle m^2 \ rangle \大约4.6 \pm0.2μ_b^2 $/fe大于122个系统，但动态相关长度相似（$ξ\ 10 $Å）。这些结果表明，尽管具有不同的磁性模式和晶格对称性，但在类似的磁交换耦合下，铁砷化铁中的超导性可能具有与局部矩和巡回电子的双重性质的共同磁性起源。
We report time-of-flight inelastic neutron scattering (INS) investigations on the spin fluctuation spectrum in the 112-type iron-based superconductor (FeSC) Ca$_{0.82}$La$_{0.18}$Fe$_{0.96}$Ni$_{0.04}$As$_{2}$ (CaLa-112). In comparison to the 122-type FeSCs with a centrosymmetric tetragonal lattice structure (space group $I4/mmm$) at room temperature and an in-plane stripe-type antiferromagnetic (AF) order at low temperature, the 112 system has a noncentrosymmetric structure (space group $P2_{1}$) with additional zigzag arsenic chains between Ca/La layers and a magnetic ground state with similar wavevector $\mathbf{Q}_{\mathrm{AF}}$ but different orientations of ordered moments in the parent compounds. Our INS study clearly reveals that the in-plane dispersions and the bandwidth of spin excitations in the superconducting CaLa-112 closely resemble to those in 122 systems. While the total fluctuating moments $\langle m^2 \rangle\approx 4.6\pm0.2 μ_B^2$/Fe are larger than 122 system, the dynamic correlation lengths are similar ($ξ\approx 10$ Å). These results suggest that superconductivity in iron arsenides may have a common magnetic origin under similar magnetic exchange couplings with a dual nature from local moments and itinerant electrons, despite their different magnetic patterns and lattice symmetries.
