Search found 604 matches

by sponce
Mon Dec 06, 2021 11:24 am
Forum: General discussion
Topic: Applicability of the EPW code for 2D and 1D nanostructures
Replies: 1
Views: 30

Re: Applicability of the EPW code for 2D and 1D nanostructures

Dear PasanH, Thank you for your interest in EPW and welcome ! At present EPW only officially support bulk 3D materials. There is ongoing work on the 2D version of EPW, which should be release soon. The 1D version is also ongoing but will likely take more time. At present EPW only supports phonon-lim...
by sponce
Mon Dec 06, 2021 11:19 am
Forum: General discussion
Topic: different phonon structure between QE and EPW
Replies: 2
Views: 43

Re: different phonon structure between QE and EPW

Dear sevenel, The phonon frequency of polar materials is ill defined exactly at q=Gamma. However it is well defined for q-->0 along a particular direction. Therefore you can safely remove the q=0 point from your plot and it should look exactly like the one obtained from matdyn.x You should not get n...
by sponce
Mon Dec 06, 2021 11:11 am
Forum: Running the code
Topic: No mobility and Scattering rates in the output
Replies: 1
Views: 1079

Re: No mobility and Scattering rates in the output

Dear Sylvester10, Please use the latest version of EPW for optimum experience. After having written the XX.wp file, you can perform a restart using: elph = .true. epbwrite = .false. epbread = .false. epwwrite = .false. epwread = .true. scattering = .true. scattering_serta = .true. int_mob = .false. ...
by sponce
Mon Oct 04, 2021 1:26 pm
Forum: Running the code
Topic: GaN-II A restart.fmt is present but not the Fepmatkqcb1 folder
Replies: 2
Views: 1108

Re: GaN-II A restart.fmt is present but not the Fepmatkqcb1 folder

Dear calos818, I do agree with H. Lee that you could try using the latest tutorial on mobility from the school. However, in the particular case of the https://docs.epw-code.org/doc/GaN-II.html tutorial, it is based on the QE test-suite which means that it should be working (this is tested every nigh...
by sponce
Mon Oct 04, 2021 1:21 pm
Forum: Running the code
Topic: Mobility calculation using epw: NaN in Hole Mobility
Replies: 1
Views: 1063

Re: Mobility calculation using epw: NaN in Hole Mobility

Dear Maitryj, A NaN in electron or hole mobility often results from the fact that your Fermi level is incorrectly set (fermi_energy) such that the Fermi level +- 'fsthick' value will fall within the bandgap. If this is the case, then there are no states that you are considering and therefore the mob...
by sponce
Mon Oct 04, 2021 1:16 pm
Forum: General discussion
Topic: GaN-II electron mobility very low while hole mobility is ok
Replies: 2
Views: 1165

Re: GaN-II electron mobility very low while hole mobility is ok

Hello, You have to adapt 'ncarrier = -1E13' to 'ncarrier = 1E13' to do electron mobility and also change the position of the Fermi level to be closer to the CBM. I could also suggest doing the more recent tutorial from the 2021 school https://epw2021.oden.utexas.edu/74-schedule scroll down that page...
by sponce
Tue Sep 14, 2021 8:48 am
Forum: General discussion
Topic: Calculation of mobility by EPW iteration
Replies: 4
Views: 2583

Re: Calculation of mobility by EPW iteration

Hello, You have to use 'int_mob = .true.' However it is not recommanded for computational reasons (more expensive that treating them separately with separate Wannierization). In addition, it the case of a large bandgap, the intrinsic carrier concentration will be very low to the point that the bisec...
by sponce
Tue Sep 14, 2021 8:40 am
Forum: Running the code
Topic: Version of EPW used in Nano Letters, 20, 8861 (2020)
Replies: 2
Views: 1361

Re: Version of EPW used in Nano Letters, 20, 8861 (2020)

Dear Vahid, The version has been released in QE 6.8 and include Hall factor. Note that 2D with only 1 k/q point along the vacuum is possible in this case because it is graphene (a non polar material) and therefore no specific 2D electrostatic is needed for the Frohlich part. For 2D polar materials, ...
by sponce
Tue Sep 14, 2021 8:08 am
Forum: Running the code
Topic: Why is my xx and yy components for mobility not the same?
Replies: 1
Views: 1110

Re: Why is my xx and yy components for mobility not the same?

Hello, The non-zero population indicates a problem such that the results cannot be trusted. This is likely due to your 4x4x4 q-point grid instead of 4x4x1. Before doing mobility calculation, you need to make sure that the electronic bandstructure and phonon bandstructure are correctly interpolated. ...
by sponce
Tue Sep 14, 2021 8:03 am
Forum: Running the code
Topic: Inquiry about high k point mesh for interpolation and population SR
Replies: 2
Views: 1225

Re: Inquiry about high k point mesh for interpolation and population SR

Hello, Note that 2D materials are not officially supported yet in EPW. You can use the EPW input variable system_2d = .true. at your own risk (with the version QE 6.8). You will need to comment out the check in EPW/src/epw_readin.f90 In any case, your phonon should also be planar like your k-grid: n...