Nagyfalusi B, Udvardi L, Szunyogh L
Wigner Research Centre for Physics, Institute for Solid State Physics and Optics, H-1525 Budapest, Hungary.
Department of Theoretical Physics, Institute of Physics, Budapest University of Technology and Economics, Műegyetem rkp. 3, H-1111 Budapest, Hungary.
J Phys Condens Matter. 2022 Jul 29;34(39). doi: 10.1088/1361-648X/ac8260.
A new computational scheme is presented based on a combination of the conjugate gradient and the Newton-Raphson method to self-consistently minimize the energy within local spin-density functional theory, thus to identify the ground state magnetic order of a finite cluster of atoms. The applicability of the newoptimization method is demonstrated for Fe chains deposited on different metallic substrates. The optimized magnetic ground states of the Fe chains on Rh(111) are analyzed in details and a good comparison is found with those obtained from an extended Heisenberg model containing first principles based interaction parameters. Moreover, the effect of the different bilinear spin-spin interactions in the formation of the magnetic ground states is monitored. In case of Fe chains on Nb(110) spin-spiral configurations with opposite rotational sense are found as compared to previous spin-model results which hints on the importance of higher order chiral interactions. The wavelength of the spin-spiral states of Fe chains on Re(0001) was obtained in good agreement with scanning tunneling microscopy experiments.
提出了一种基于共轭梯度法和牛顿-拉夫逊法相结合的新计算方案，以在局部自旋密度泛函理论中自洽地最小化能量，从而确定有限原子簇的基态磁序。针对沉积在不同金属衬底上的铁链，证明了这种新优化方法的适用性。详细分析了Rh(111)上铁链的优化磁基态，并与从包含基于第一性原理的相互作用参数的扩展海森堡模型获得的结果进行了很好的比较。此外，监测了不同双线性自旋-自旋相互作用在磁基态形成中的作用。对于Nb(110)上的铁链，发现与先前的自旋模型结果相比，具有相反旋转方向的自旋螺旋构型，这暗示了高阶手性相互作用的重要性。Re(0001)上铁链的自旋螺旋态波长与扫描隧道显微镜实验结果吻合良好。
