Dear all, I have a question regarding the implementation of the k-gradient.
1) In Wannier90, it is implemented by constructing the weights such that the completeness relation is fully satisfied [Eq. (B1), PRB 56, 12847 (1997)].
2) Another approach would be to calculate the numerical derivatives along the reciprocal lattice vectors (which is easy as the quantities are given in a Monkhorst-Pack grid), and then transform to the Cartesian coordinates using the metric tensor and the reciprocal lattice vectors.
I am wondering why approach 1) was implemented over approach 2) in Wannier90. The second approach seems to be easier, or does approach 2) fail in some cases?
Best regards, Lun Yue Louisiana State University _______________________________________________ Wannier mailing list Wannier@lists.quantum-espresso.org https://lists.quantum-espresso.org/mailman/listinfo/wannier
