Calculating Ideal strength of crystal using vasp.

Introduction

Calculating Ideal strength of crystal using vasp. PRL 82,2713(1999)

Details

First you need to modify vasp code. If you want to calculate ideal tensile strength, you should add 'FCELL(1,1)=0.0' to constr_cell_relax.F of vasp code. And if you choose ideal shear strength, you should add 'FCELL(1,3)= 0.0' and 'FCELL(3,1) = 0.0' to constr_cell_relax.F of vasp code. Here, you need to recompile vasp.

second, you should prepare input.dat and this file as below:

POSCAR

0.02 #strain

20 #step

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

1 # 1 tensile, 2 shear

mpiexec -np 8 vasp.4.6

The first line is the name of POSCAR. The second line is strain of distortion. The third line is total step of distortion. The fourth line is degree of rotation. This is for calculating special orientation. 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. The five line is to choose tensile of shear. The sixth line is execute command.

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