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zhzailan

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[交流] 【求助】关于体系initial-spin-scale的设置已有2人参与

计算石墨带考虑自旋的话，initial-spin-scale要怎么设置呢。说明书里面的2个边缘给+1和-1其他的给0。这是出于什么考虑？如果我们计算别的体系，这个初始值要怎么得到？要做什么计算，做什么分析得到吗？还是随便给就行的呢？

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1楼 2010-04-03 22:35:58

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tiejun8046

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zhzailan(金币+8):恩，好的 2010-04-12 17:41
qasd(金币+2):谢谢 2010-04-12 22:03

Before doing the spin-polarized calculation of a two-probe system, one had better separately do the spin-polarized calculations for the electrodes and the conductor object (in the center region and exclude the surface layers) to find out their most stable magnetic states( ferromagnetic, antiferromagnetic, non-magnetic, or other states). If the systems are magnetic, you would obtain the local magnetic moment for each atom in these systems. These obtained results will be good starting point for the setup of "initial_scaled_spin" for the spin-polarized calculation of the corresponding two-probe system.

The different values for the "initial_scaled_spin" of each atom could lead to the calculations being converged to different magnetic states.  They could also affect the convergence speed of self-consistent calculation.

For a two-probe system, the setup of "initial_scaled_spin" depends on the magnetic state of each part (electrodes and conductor) of two-probe system. It also depends on the problem under study.

For example, see the following cases:
i) the two electrodes are non-magnetic, and the conductor is magnetic:
  "initial_scaled_spin" for atoms in electrodes and the ones in the surface layers of center region:  0.0
ii) the two electrode are ferromagnetic, and the conductor is nonmagnetic:
  "initial_scaled_spin" for atoms in the conductor:  0.0
There are two spin configurations for other parts:
a) parallel spin alignment: "initial_scaled_spin" for atoms in left electrode and the ones in the left surface layers of center region are same as those of right electrode and the right surface layer, respectively.
b) anti-parallel spin alignment: "initial_scaled_spin" for atoms in left electrode and the ones in the left surface layers of center region are opposite to those of right electrode and the right surface layer, respectively.