EPW Forum

Hi Ashwath, Before jumping into the ME calculations, the most important step is the wannierization. Please make sure that your W90 bands fits well with the DFT and the spreads are reasonably small (< 5 Ang.), then perform the Block to Wann calculation. for dynamical matrices, etc in the coarse grid ...

Hi Shubham, You currently have "max_memlt = 18.0d0" specified in the input, meaning this is the maximum amount of memory can be allocated per pool. Is this value set to the maximum available memory per core in the cluster you are using? The code crashed because the memory requirement is ...

Hi Timon, It seems the code did not properly read the NbSe2.ephmat/freq file. As I recall, this was a known bug in the implementation at the time of QE 7.2 and EPW 5.7. The issue has since been resolved in newer versions, specifically QE 7.3 with EPW 5.8.1. Upgrading to the latest version should ...

Hi jhosamelly, The time required for a phonon calculation depends on several factors, especially the k-mesh used in the SCF calculation and the q-mesh for the phonon calculations. Since your supercell is sufficiently large, smaller meshes could improve computational efficiency. For efficiency, and ...

Hi,

In addition to the Hitoshi's comment, please consider checking the value of el-ph coupling strength. It looks unphysical.

Happy EPWing,
Hari

Hi Shunshun Liu, As far as I am aware, the official release version of EPW does not have such features explicitly, as these types of calculations are highly system-dependent. I would suggest identifying the pi and sigma pockets in the Fermi surface. Based on this, you can separate those pockets by ...

Hi Jianguo Si,

Could you double check your 'selecq.fmt' file and make sure all the q-points along the high symmetry path are included? It looks like those q-points are excluded in your calculation.

Happy EPWing,
Hari

Hi Jykun, The error message explains clearly "coarse k-mesh needs to be strictly positive in 1st BZ". The uniform k-mesh you have provided in the 'nscf.in' are not positive in the 1st BZ, need to define a homogeneous k-grid. I suggest, the homogeneous k grid for the non self-consistent calculations ...

Hi Shubham,

That's great.

Happy EPWing,
Hari

Hi Shubham, Could you double check your nscf.out file if it has 216 k-points printed or not? Sometimes, because of symmetry, QE prints more number of k-points that the supplied. If it is so, I recommend using 'calculation = 'bands'' instead of 'nscf' in the nscf.in. I hope it helps. Happy EPWing ...