QuantumATK Forum

QuantumATK => General Questions and Answers => Topic started by: markmick on March 28, 2016, 09:08

Title: Different Unit Cells for MoS2
Post by: markmick on March 28, 2016, 09:08

I've created two MoS2 poscars; one from VNL and another from Python-ASE.  Attached are the files.  Why are there different variations for the hexagonal MoS2 unit cell?  Are there any advantages?

Title: Re: Different Unit Cells for MoS2
Post by: zh on March 28, 2016, 15:35

These atomic positions in both files are symmetry equivalent, except the slightly different lengths of lattice constants.

 0.333333333333   0.666666666667   0.500407000407  T T T
  0.666666666667   0.333333333333   0.371301994302  T T T
  0.666666666667   0.333333333333   0.629512006512  T T T

-( 0.333333333333   0.666666666667   0.000407000407)

=
 0.000000000000   0.000000000000   0.500000000000  T T T
  .....
  .....

translational symmetry