Re: [QE-users] Error in piezoelectric coefficients calculation (Berry phase)

Thats because nbnd is only used for calculation type BANDS On Fri, 4 Aug 2023 at 19:43, Zimmi Singh wrote:Dear Users,I am attempting to calculate the piezoelectric coefficients of 2D MoS2 using the Berry Phase method on a strained structure (0.5% in the armchair direction). I faced two issues du

Re: [QE-users] Negative frequencies for phonon dispersion in Bilayer MoS2

Try CRYSTAL 23 or vesta On Fri, 4 Aug 2023 at 16:23, Giuseppe Scala wrote:I used a YouTube tutorial with BURAI for creating this input file, sigh. What should I do to create a right Bilayer using Burai or another software? Il ven 4 ago 2023, 12:14 ANAND JHA ha scritto:Its wr

[QE-users] Error in piezoelectric coefficients calculation (Berry phase)

Dear Users, I am attempting to calculate the piezoelectric coefficients of 2D MoS2 using the Berry Phase method on a strained structure (0.5% in the armchair direction). I faced two issues during the process. 1) In the nscf calculations, I added the 'nbnd' tag in the input file ( nscf1.in). Howev

Re: [QE-users] Negative frequencies for phonon dispersion in Bilayer MoS2

I"m really grateful for the time you're dedicating to me. I tried tonight with lower tr2_ph and using a 4 4 1 k-point grid and the negative frequencies disappeared. Now I'm trying again with nq1=nq2=3 in order to improve the dispersion relation. In regards to occupation = 'smearing', I'm using It b

Re: [QE-users] Negative frequencies for phonon dispersion in Bilayer MoS2

A few points about your inputs: 1. You may want to lower both force and energy convergence thresholds by a factor of 10 2. You are using smearing. Is this a metal? If not, try a fixed occupation 3. For a bilayer, the KPOINTS should be like 4 4 1 or 6 6 1. From experience, since your a=3 angstr

Re: [QE-users] Negative frequencies for phonon dispersion in Bilayer MoS2

If the coordinates of the atoms are correct for the bilayer, you just need to add vacuum by adding 15 to 20 Ang to the c value. Cheers, Vahid Vahid Askarpour Department of Physics Dalhousie University Halifax, NS CANADA On Aug 4, 2023, at 7:08 AM, Giuseppe Scala wrote: CAUTION: The Sender of

Re: [QE-users] Negative frequencies for phonon dispersion in Bilayer MoS2

I used a YouTube tutorial with BURAI for creating this input file, sigh. What should I do to create a right Bilayer using Burai or another software? Il ven 4 ago 2023, 12:14 ANAND JHA ha scritto: > Its wrong > Becauese vaccume will be after the top surface of bilayer so u need to add > vaccume o

Re: [QE-users] Negative frequencies for phonon dispersion in Bilayer MoS2

Its wrong Becauese vaccume will be after the top surface of bilayer so u need to add vaccume on your top bilayer On Fri, 4 Aug 2023 at 15:38, Giuseppe Scala wrote:The c parameter is set in that way in order to have 10 angstrom vacuum between two sets of Bilayer in my structure. If I reduce the c p

Re: [QE-users] Negative frequencies for phonon dispersion in Bilayer MoS2

The c parameter is set in that way in order to have 10 angstrom vacuum between two sets of Bilayer in my structure. If I reduce the c parameter i think that my system won't be a Bilayer anymore. Is that line of reasoning wrong? Il ven 4 ago 2023, 05:15 ANAND JHA ha scritto: > C parameter and a p