Dear Haci,
there is no such thing as utlimately correct band structure,
there is always your free choice how to choose the path along which
the bands are shown. But, usually it makes sense to explore
a path connecting several symmetric points. Let's think together
how to get them.
Back to textbooks. Your lattice is orthorhombic with a,b,c.
Correspondingly your reciprocal lattice is orthorhombic
with parameters 2*pi/a, 2*pi/b, 2*pi/c. So good candidates
for symmetry points are
Gamma=(0,0,0), X=(pi/a,0,0), Y=(0,pi/b,0), Z=(0,0,pi/c),
and some their combinations. Now think how to define them.
Siesta offers you two possibilities:
EITHER in units of pi/a,
in which case the definition would be
X - (1,0,0), Y- (0, a/b,0), Z- (0,0,a/c)
OR in units of reciprocal lattice vectors,
in which case the definition would be
X - (0.5, 0,0), Y-(0, 0.5, 0), Z- (0,0, 0.5).
My impression is that you combine the units definition
as in the first possibility with the definition of vectors
as in the second possibility.
Good luck,
Andrei Postnikov
