Hello Steve Sir,
Using the different unit cell i able to solve that.
But the lattice primitive vectors collinear is not solved. As you suggested to follow this:
variable a equal 1/sqrt(2)
lattice custom 1 a1 a a 0.0 a2 -a a 0.0 a3 0 0 1 basis 0 0 0 basis 0.0 0.5 0.5
Then also there is the same problem.
Thanking you
apurba
You need this:
variable a equal 1/sqrt(2)
variable nega equal -1/sqrt(2)
lattice custom 1 a1 $a a 0\.0 a2 {nega} $a 0.0 a3 0 0 1 &
basis 0 0 0 basis 0.0 0.5 0.5
Steve