Contents
  1. 1. INCAR
  2. 2. POSCAR
  3. 3. KPOINTS
  4. 4. POTCAR
  5. 5. 计算结果 CONTCAR

最近看了一篇文章,是关于铬的卤化物 CrX3 的诸多性质的计算

Robust intrinsic ferromagnetism and half semiconductivity in stable two-dimensional single-layer chromium trihalides
Wei-Bing Zhang et al.

我尝试着重复这篇文章里的计算。因为我对整个计算流程其实不太熟悉,所以在此详细记录一下整个过程,作为学习笔记。

INCAR

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     SYSTEM = CrI3 bulk
ISIF = 3
NSW = 1000
EDIFF = 1E-5
EDIFFG = -5E-3
PREC = High
IBRION = 2
ISMEAR = 0
ISPIN = 2
ENCUT = 600
#vdw
#GGA = RE
#LUSE_VDW = .TRUE.
#AGGAC = 0.0000

各个参数的意义,待说明

POSCAR

具体参考上一篇博客 如何得到 CrI3 bulk 的 POSCAR

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CrI3 bulk system
1.0
7.7013001442 0.0000000000 0.0000000000
4.6397266689 6.1467845536 0.0000000000
4.6397266689 2.3109422460 5.6958323610
I Cr
6 2
Direct
0.419150014 0.070070001 0.767089986
0.580850148 0.929929961 0.232909974
0.767089920 0.419150013 0.070069996
0.232909981 0.580850061 0.929929980
0.070069968 0.767090064 0.419149980
0.929930017 0.232909969 0.580850001
0.167169998 0.167170023 0.167169997
0.832829889 0.832830068 0.832829984

KPOINTS

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k-points
0
Monkhorst Pack
8 8 8
0 0 0

kpoints 的选取是按照论文中的取法

K -points sampling with a mesh of 8×8×8 kpoints generated by the scheme of Monkhorst-Pack is used for a primitive cell of bulk CrX3 as shown in Fig. 1- (b).

POTCAR

论文里提到用赝势用 PAW_PBE 的方法

The present calculations have been performed with spin-polarization using the Vienna ab initio simulation package (VASP) code20,21 within projector augmentedwave (PAW) method22,23. General gradient approximations (GGA) in the Perdew-Burke-Ernzerhof(PBE) implementation24 are applied as the exchange correlation functional.

因此,先找到 PAW_PBE 的目录,因此导入 I 和 Cr 的POTCAR,再将 POTCAR 转移到计算目录下即可

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$ zcat /share/apps/src/vasp/pseudopotential/paw_pbe/I/POTCAR.Z > POTCAR
$ zcat /share/apps/src/vasp/pseudopotential/paw_pbe/Cr/POTCAR.Z >> POTCAR

计算结果 CONTCAR

计算完成得到了 CONTCAR, 与上一篇博客得到POSCAR 的操作类似,把 CONTCAR 导入 VESTA 得到 cif,再导入 Materials studio,通过 Find Symmetry 可以得到结构优化以后的晶格参数 a 和 c,如下图

对比论文中给出的实验数据

在开始计算时,我输入POSCAR的是 rhombohedral structure, a = 6.867 A,c = 19.807 A,第一步结构优化得到的 CONTCAR 显示优化后 a = 7.0038 A, c = 22.4418。与论文中 PBE 计算的 CrI3 的结果 7.006 和 22.35 可以说是基本一致了。

Contents
  1. 1. INCAR
  2. 2. POSCAR
  3. 3. KPOINTS
  4. 4. POTCAR
  5. 5. 计算结果 CONTCAR