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arXiv 1609.07648cond-mat.str-el
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Si(111):{C,Si,Sn,Pb}中的自旋轨道耦合和磁相互作用

Spin-orbit coupling and magnetic interactions in Si(111):{C,Si,Sn,Pb}

D. I. Badrtdinov, S. A. Nikolaev, M. I. Katsnelson, V. V. Mazurenko

摘要:

研究了半导体表面Si(111):C,Si,Sn,Pb-($\sqrt{3} \times \sqrt{3}$)吸附原子体系的磁性.在全电子密度泛函理论计算的基础上,考虑自旋轨道耦合和电子关联,建立了有效的低能模型。在基态的表面纳米结构被发现是绝缘体与非共线的120 $^{\circ}$ Néel(对于C,Si,Sn单层覆盖)和120 $^{\circ}$行向(对于Pb吸附原子)的反铁磁排序。利用超交换理论导出了具有各向异性交换相互作用的自旋哈密顿量,计算得到的Dzyaloshinskiii-Moriya相互作用非常强,与Sn和Pb吸附原子系统中的各向同性交换耦合相容.为了模拟激发磁态,我们通过Monte Carlo方法求解所构建的自旋模型。在低温和零磁场条件下,我们在Sn/Si(111)和Pb/Si(111)中观察到了复杂的自旋螺旋花样。在此基础上讨论了强磁场中吸附原子$sp$电子系统反铁磁Skyrmion晶格态的形成。

英文摘要:

We study the magnetic properties of the adatom systems on a semiconductor surface Si(111):\{C,Si,Sn,Pb\} - ($\sqrt{3} \times \sqrt{3}$). On the basis of all-electron density functional theory calculations we construct effective low-energy models taking into account spin-orbit coupling and electronic correlations. In the ground state the surface nanostructures are found to be insulators with the non-collinear 120$^{\circ}$ Néel (for C, Si, Sn monolayer coverages) and 120$^{\circ}$ row-wise (for Pb adatom) antiferromagnetic orderings. The corresponding spin Hamiltonians with anisotropic exchange interactions are derived by means of the superexchange theory and the calculated Dzyaloshinskii-Moriya interactions are revealed to be very strong and compatible with the isotropic exchange couplings in the systems with Sn and Pb adatoms. To simulate the excited magnetic states we solve the constructed spin models by means of the Monte Carlo method. At low temperatures and zero magnetic field we observe complex spin spiral patterns in Sn/Si(111) and Pb/Si(111). On this basis the formation of antiferromagnetic skyrmion lattice states in adatom $sp$ electron systems in strong magnetic fields is discussed.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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