vasp 应力应变曲线

 科学网—Ideal strength VASP by Hanyu Liu - 冯晓蕾的博文 (sciencenet.cn)

The original method is introduced by PRL 82,2713(1999)

本文为本人工作记录。程序下载及计算方法请到 https://sourceforge.net/projects/ideal-strength-vasp/?source=navbar

感谢本程序作者：

Dr. Hanyu Liu

Email: hanyuliu801@gmail.com

准备工作

1.结构优化。将CONTCAR到出，在MS中导入对称性， 再转为POSCAR（for further calculations）

2.编译VASP。把VASP安装包cp到自己的目录。

 for ideal tensile strength, add 'FCELL(1,1)= 0.0' to constr_cell_relax.F of vasp code.

#the Stress at x axis is fixed and vasp not relax the lattice at x axis.

 for ideal shear strength, add 'FCELL(1,3)= 0.0' and 'FCELL(3,1) = 0.0' constr_cell_relax.F of vasp code.

 Here, you need to recompile vasp. 【make clean 】【make】

我在make的过程除了error： 没有lib。Lib文件放在mu'lu中，改下路径ming ，OK！

输入文件

0. pbs.sh (集群上提交任务的脚本 ./strenth4.py > Strength.log)

1.POSCAR

2. POTCAR

3. KPOINTS (不用太大： ./writekp.py 0.04)

4. strength4.py (核心程序，下载到Hanyu主页，见文章开篇)

5. input.dat (strength4.py 要读的输入文件) as followed:

POSCAR #the name of POSCAR

0.02 #strain of distortion

100 #total step of distortion (虽说一般30steps即可，建议设置大一些，因为数据够了的话可以手动kill job)

-45.0 35.264390 0.0 # rotate Z, Y and X.

1 # 1 tensile, 2 shear

/home/zzu002/lhy/test/vasp/vasp.5.3-1/vasp # 提任务的命令。注意tensile和shear

的vasp路径不同！

关于计算的方向：

We set x axis as tensile strength direction (tensile (x)). Also we set x and z axis as shear direction (shear (x)[z]). For example, if you want to calculating ideal strength of Diamond along 100, you just set 0.0 0.0 0.0. If you want to calculate 110 orientation, you need set -45.0 0.0 0.0

If you want to calculate 111 orientation, you need set -45.0 35.264390 0.0.

It is for rotating the x, y and z axis as a Right-handed helical rule.

我计算的tensile plane：

TENSILE
dire  input#rotate Z, Y, X.    GPa      jobID  jobState

100    0.0 0.0 0.0               103.115345   53421  killed
110  -45.0 0.0 0.0              100.23066    53422  killed
111  -45.0 35.264390 0.0  120.147138   53463  killed
001    0.0 90.0 0.0                75.300806   53464  killed
010  -90.0 0.0 0.0              122.560777   53465  killed

101    0.0 45.0 0.0                75.7             54584
011  -90.0 45.0 0.0               64               54585
+101    0.0 -45.0 0.0              82               54586
+110    45.0 0.0 0.0                                  54587  =<110> killed
11+1  -45.0 -35.26439 0.0    10.961293    54953

SHEAR-001

1 0.0  90.0 0.0                           55035
2 0.0  90.0 90.0                          55036
3 0.0  90.0 180.0                         55161

Research highlights:

1, Miao Zhang, Mingchun Lu, Yonghui Du, Lili Gao, Cheng Lu and Hanyu Liu, "Hardness of FeB4?: Density functional theory investigation" J. Chem. Phys., 140, 174505 (2014)

2, Yinwei Li, Jian Hao, Hanyu Liu, Siyu Lu and John S. Tse "High energy density and superhard nitrogen-rich B-N compounds", Phys. Rev. Lett., 115, 105502 (2015)

3, Miao Zhang, Hanyu Liu, Quan Li, Bo Gao, Yanchao Wang, Hongdong Li, Changfeng Chen and Yanming Ma, “Superhard BC3 in cubic diamond structure” Phys. Rev. Lett., 114, 015502 (2015)

4, Quan Li, Hanyu Liu, Dan Zhou, Weitao Zheng, Zhijian Wu and Yanming Ma, "novel low compressible and superhard carbon nitride: Body-centered tetragonal CN2" Phys. Chem. Chem. Phys., 14, 13081–13087 (2012)