Dear Subhashish Tiwari,
I’m sorry the answers are not coming faster, we are doing the best we can. This is a community forum, so things could take a little more time. For urgent requests, please don’t hesitate to contact us directly at support@optiwave.com. We always give priority to our licensed customers.
Concerning your problem, the k-vector indexes are linked to the k-vector path which is defined in the user’s reference manual, page 76:
—
K-Vector Path area
Specifies data used to generate the k-vector point along a k-vector path in the Brillouin
zone of reciprocal lattice.
The PWE method solves all the required eigenvalues (band) based on each k-vector
point. The path is defined by set of major k-points and the associated number of
divisions along the path from one major vector to another
—
Each individual k-index correspond to a division along the k-path. If you used the predifined square ZX path, the points are as follows:
G is the k-point #0
X is a point #6 (5 divs)
M is at #10
G is at #15
It corresponds to the band diagrams definitions used in this book:
http://ab-initio.mit.edu/book/