论文标题
与自旋依赖性跳跃的局部力量方法的局部力量方法
Local force method for the ab initio tight-binding model with spin-dependent hopping
论文作者
论文摘要
为了估算第一原理中金属磁体的质地温度，我们开发了一种局部力量方法，用于具有从自旋密度函数理论衍生的自旋依赖性跳跃的紧密结合模型。虽然依赖自旋的跳跃对于对有效旋转模型的自洽映射至关重要，但在常规绿色的功能方案中处理这种非本地术语的数值成本非常昂贵。在这里，我们提出了一种基于内核多项式方法（kpm）的形式主义，该方法使计算显着有效。我们对BCC-FE，FCC-CO和FCC-NI执行基准计算，发现磁非本地项的效果对于BCC-FE尤为突出。我们还向磁性非本地术语提供了几个局部近似值，我们可以通过利用绿色功能的中间表示，进一步应用绿色的功能方法并进一步降低数值成本。通过比较KPM和本地方法的结果，我们讨论了哪种局部方法最成功。我们的方法提供了一种有效的方法，可以通过复杂的自旋构型估算金属磁体的质量温度。
To estimate the Curie temperature of metallic magnets from first principles, we develop a local force method for the tight-binding model having spin-dependent hopping derived from spin density functional theory. While spin-dependent hopping is crucial for the self-consistent mapping to the effective spin model, the numerical cost to treat such non-local terms in the conventional Green's function scheme is formidably expensive. Here, we propose a formalism based on the kernel polynomial method (KPM), which makes the calculation dramatically efficient. We perform a benchmark calculation for bcc-Fe, fcc-Co, and fcc-Ni and find that the effect of the magnetic non-local terms is particularly prominent for bcc-Fe. We also present several local approximations to the magnetic non-local terms for which we can apply the Green's function method and reduce the numerical cost further by exploiting the intermediate representation of the Green's function. By comparing the results of the KPM and local methods, we discuss which local method works most successfully. Our approach provides an efficient way to estimate the Curie temperature of metallic magnets with a complex spin configuration.
