论文标题
评估自旋波刚度从头算的不同方法
Assessing different approaches to ab initio calculations of spin wave stiffness
论文作者
论文摘要
从头开始计算元素Fe的自旋刚度常数$ d $和过去由不同群体执行的NI的ni导致了值，相当大的差异为50-100％。我们介绍了刚度恒定的$ d $ d $ fe，ni和permalloy fe $ _ {0.19} $ ni $ _ {0.81} $通过三种不同方法获得的结果：（i）通过在潮湿的波动分散（II）中（ii）汇总的（ii）的（ii）的（ii）的（ii）汇总（ii）的（ii）的（ii）通过降低的次数汇总（ii）的（ii）的（ii）汇总（ii）的（ii）的（ii）的（ii）的（II相互空间。所有方法都是通过相同的Korringa-Kohn-Rostoker（KKR）绿色功能形式主义实施的。我们证明，如果正确收敛，所有程序都会产生可比的值，不确定性剩余5-10％。通过仔细分析各种技术参数的影响，我们估算了通过不同方法评估的刚度常数的错误余量，并建议采用的程序，以最大程度地减少获得不正确结果的风险。
Ab initio calculations of the spin wave stiffness constant $D$ for elemental Fe and Ni performed by different groups in the past have led to values with a considerable spread of 50-100 %. We present results for the stiffness constant $D$ of Fe, Ni, and permalloy Fe$_{0.19}$Ni$_{0.81}$ obtained by three different approaches: (i) by finding the quadratic term coefficient of the power expansion of the spin wave energy dispersion, (ii) by a damped real-space summation of weighted exchange coupling constants, and (iii) by integrating the appropriate expression in reciprocal space. All approaches are implemented by means of the same Korringa-Kohn-Rostoker (KKR) Green function formalism. We demonstrate that if properly converged, all procedures yield comparable values, with uncertainties of 5-10 % remaining. By a careful analysis of the influence of various technical parameters we estimate the margin of errors for the stiffness constants evaluated by different approaches and suggest procedures to minimize the risk of getting incorrect results.
