On 11/12/17 23:21, Francesco Delodovici wrote: > 1) the out-of-plane acoustic branch at low wave vector is not quadratic, > istead is linear.
This would indicate that your mono-layer structure is strained, although you say you did a vc-reax, you may try to double-check this part. What if you relax the bulk and then you use the bulk parameter? Anyway, the branch will always be linear very close to Gamma, because we are using are really doing a 3D calculation, with vacuum, using more q-points may also help. > 2) Since I don't include the flag epsil='true' there is no LO-TO > splitting, but the slope of the LO branch is vanishing at Gamma Otherwise, you may want to check the work of Thibault Sohier, Matteo Calandra, and Francesco Mauri. Phys. Rev. B 91, 165428. It is implemented in the development version of the code, and it should be in in the upcoming 6.2.1 version of QE, check PHonon/examples/example17 hth -- Lorenzo Paulatto - Paris _______________________________________________ Pw_forum mailing list [email protected] http://pwscf.org/mailman/listinfo/pw_forum
