Re: [QE-users] Reg - Absorption spectrum study

2022-04-28 Thread Iurii TIMROV via users 
Dear Vivek,


I used turbo_eels.x to compute the absorption spectrum (Im(eps)) for bulk Bi: 
https://journals.aps.org/prresearch/abstract/10.1103/PhysRevResearch.3.033210



Greetings,

Iurii


--
Dr. Iurii TIMROV
Senior Research Scientist
Theory and Simulation of Materials (THEOS)
Swiss Federal Institute of Technology Lausanne (EPFL)
CH-1015 Lausanne, Switzerland
+41 21 69 34 881
http://people.epfl.ch/265334

From: users  on behalf of Vivek 
Christhunathan 
Sent: Wednesday, April 27, 2022 11:15:21 PM
To: Quantum ESPRESSO users Forum
Subject: [QE-users] Reg - Absorption spectrum study

Hello Everyone,

I tried to predict the absorption spectrum properties of pure and TM cations 
-doped TiO2 by using turbo_davidson, turbo_lanczos, and epsilon.x methods. But 
I could not bring results due to multiple issues with TDDFT (i.e., PPs issues 
and metallic properties of the material issues, etc). To study the absorption 
spectrum of TiO2, I used turbo_eels.x method and produced fine graphs 
(wavelength vs absorption) whose values (such as maximum absorption point and 
absorption edge) are in good agreement with existing DFT work.

I'm wondering if I can use this absorption spectrum results in a research 
paper. If any of you have done something similar (such as developing an 
absorption spectrum using the turbo_eels.x approach) in your DFT work and had 
it published in a journal, I request you please email me with more details so 
that I can use it for citation. It would be very helpful for me in my research.

Thanking you.

Kind Regards,
Vivek Christhunathan
PhD researcher
Mechanical Engineering
College of Engineering and Informatics
Alice Perry Engineering Building
National University of Ireland Galway, Ireland
E-mail: v.christhunath...@nuigalway.ie
Phone: +353 899811181, +91 9600752742
[https://docs.google.com/uc?export=download=1oPtxd7PT5ljQRnuP-Gdf5upjiKPXk7Fz=0B_S3ZLbRRu26NW1YallITFk1ZHMxaStQaUVoMjZ4M2NqcC9BPQ]
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Re: [QE-users] Error - unknown cell_dofree ibrav

2022-04-28 Thread remya ud 
Dear all,
Finally, the 'unknown cell_dofree 'ibrav ' error that occurred during VC
relaxation calculation is solved. Initially, I installed pw.x of the old
version. Recently, Q.E.7.0 is installed. But the program was running on the
previous version.
Sorry for the inconvenience.
thank you

On Thu, Apr 28, 2022 at 10:46 AM remya ud  wrote:

> Dear all,
> I am trying to do the vc_relax calculation of Si. But it cracked with an
> error
> task # 0
>  from  init_dofree: error # 1
>   unknown cell_dofree ibrav
>
> I am using the 7.0 version of the Quantum espresso. And also checked in
> Modules/cell_base.f90 as suggested by the mailing list. When I tried with
> 'all', 'shape', and 'volume', they didn't show similar errors. Kindly
> correct me where I went wrong in the calculation since 'ibrav' is working
> for others.
>
> Input file is
> 
> calculation ='vc-relax'
> prefix = 'si'
> outdir = './ outdir'
> pseudo_dir = '.'
> etot_conv_thr = 1e-5
> forc_conv_thr = 1e-4
>  /
>
>  
> ibrav = 2
> celldm(1) = 14
> nat = 2
> ntyp = 1
> ecutwfc = 30
>  /
>
>  
>conv_thr=1.e-7
>  /
> 
> /
> 
>cell_dofree='ibrav'
> /
> ATOMIC_SPECIES
>  Si  28.0855  Si.pbe-n-rrkjus_psl.1.0.0.UPF
>
> ATOMIC_POSITIONS alat
>  Si 0.00 0.00 0.00 0 0 0
>  Si 0.25 0.25 0.25 0 0 0
>
> K_POINTS automatic
>   4 4 4 0 0 0
>
>
> The  subroutine start with
> SUBROUTINE init_dofree ( cell_dofree )
>  !! Set constraints on cell dynamics/optimization
>
>  CHARACTER(LEN=*), INTENT(IN) :: cell_dofree
>  CHARACTER(LEN=80) :: cell_dofree_
>
>  IF(cell_dofree(1:5) == 'ibrav') THEN
>iforceh = 1
>enforce_ibrav = .true.
>IF(cell_dofree(6:6)=="+")THEN
>  cell_dofree_ = cell_dofree(7:)
>ELSE
>  cell_dofree_="default"
>ENDIF
>  ELSE
>cell_dofree_ = cell_dofree
>  ENDIF
>
>  SELECT CASE ( TRIM( cell_dofree_ ) )
>
> CASE ( 'all', 'default', '' )
>   iforceh = 1
> !CASE ('ibrav')
>   !iforceh = 1
>   !enforce_ibrav = .true.
> CASE ( 'shape' )
>   iforceh = 1
>   fix_volume = .true.
> Kindly suggest some solution to solve this.
>
>
>
> --
>
> *Remya. U. D*
>
> *Research Scholar*
> *Intermetallics and Nonlinear Optical Lab*
> *National Institute of Technology*
> *Tiruchirappalli, Tamil Nadu*
> *India*
>
>
>

-- 

*Remya. U. D*

*Research Scholar*
*Intermetallics and Nonlinear Optical Lab*
*National Institute of Technology*
*Tiruchirappalli, Tamil Nadu*
*India*
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Re: [QE-users] Regarding bands

2022-04-28 Thread Satyasiban Dash ph19d005 
Thank you for your response.

On Thu, 28 Apr, 2022, 5:57 pm Giuseppe Mattioli, <
giuseppe.matti...@ism.cnr.it> wrote:

>
> Dear Satya
>
> Like Giovanni, I also don't know why you don't obtain what you expect.
> But I want to offer my own penny to the discussion.
>
> 1) Due to the well known effect of delocalization errors in GGA-DFT,
> the band gap of Si is generally reduced to around 0.6 eV. The
> reduction involves both the lowering of the conduction band potential
> and the raising of the valence band potential. In the case of ZnO you
> have a strongly curved conduction band around the minimum at Gamma,
> which is not affected by delocalization errors, and a very problematic
> valence band, in which the interaction between the narrow O 2p and Zn
> 3d contributions may raise the valence band maximum by more than 2 eV,
> shrinking the band gap to less than 1 eV in bulk ZnO.
>
> 2) First of all, therefore, I would check *in the same supercell* if
> isolated Si and isolated ZnO slabs envisage a metallic character of
> the junction due to the unsymmetrical band gap underestimation of the
> two parts.
>
> 3) The most stable ZnO surface is (10-10), not 0001 (or its 000-1
> counterpart having reverse polarity). The polar surfaces of ZnO are
> tricky to simulate as slabs due to the strong polarity of the Zn-O
> bond. In the past, I obtained some weird layered hexagonal structure
> similar to BN! I suppose that the choice of (0001) is purposeful. If
> it is not, try to reconsider your choice.
>
> 4) Such a strongly polar surface in contact with a non-polar Si
> surface may induce a huge interfacial charge transfer, even enhanced
> by delocalization errors mentioned above, or can lead to significant
> shifts of band edges, yielding a metallic character of the
> semiconductor junction.
>
> HTH
> Giuseppe
>
> Quoting Satyasiban Dash ph19d005 :
>
> > Yes . Thank you for the clarification. I am trying to match (0001)
> surface.
> > But I have observed upon relaxing ZnO loosing its symmetry and this may
> be
> > due to the polar surfaces but experimentally we do observe a band gap. I
> > have also tried dipole correction but results are same. But if I remove
> Si
> > its giving a gap. Is there anyway to reproduce it with Si (001).
> >
> > On Thu, 28 Apr, 2022, 4:55 pm Giovanni Cantele, <
> > giovanni.cant...@spin.cnr.it> wrote:
> >
> >> Dear Satya,
> >>
> >> it is not that easy (at least for me) to provide an answer to your
> >> question using the data you have provided. Maybe the output files (of
> scf
> >> and bands) and a plot of your band structure might help to infer if
> there
> >> is any issue in your calculation.
> >>
> >> However, before wondering whether you get a metal whereas experiments
> >> measure a gap, you should also check that you are simulating a system
> that
> >> is as close as possible to the experimental one (in terms of thickness
> >> and/or surface orientation of both ZnO and Si, and so on). As far as the
> >> atomic positions are concerned, they look reasonable. It seems (if I’m
> not
> >> wrong) that you are trying to match a Si(100) surface with a ZnO(0001)
> >> surface, aren’t you? Is this what you expect?
> >>
> >> Giovanni
> >>
> >> --
> >>
> >> Giovanni Cantele, PhD
> >> CNR-SPIN
> >> c/o Dipartimento di Fisica
> >> Universita' di Napoli "Federico II"
> >> Complesso Universitario M. S. Angelo - Ed. 6
> >> Via Cintia, I-80126, Napoli, Italy
> >> e-mail: giovanni.cant...@spin.cnr.it 
> >> Phone: +39 081 676910
> >> Skype contact: giocan74
> >>
> >> ResearcherID: http://www.researcherid.com/rid/A-1951-2009
> >> Web page: https://sites.google.com/view/giovanni-cantele/home
> >>
> >>
> >> On 28 Apr 2022, at 07:09, Satyasiban Dash ph19d005 <
> >> ph19d...@smail.iitm.ac.in> wrote:
> >>
> >> Dear Users
> >>  I have been trying to calculate a heterostructure with a slab model. I
> >> have followed most of the examples given in the forum and tried it
> still I
> >> am getting a metallic band structure. I have used the K-path generation
> >> tool provided in "material project" website  to generate k-path. I have
> >> given the scf and bands.in file as attached files. Please have a look.
> >> Experimentally this system has a wide band gap.
> >>
> >>
> >> Thanks.
> >> Satya
> >> Research Scholar
> >> IIT Madras.
> >>  >___
> >> The Quantum ESPRESSO community stands by the Ukrainian
> >> people and expresses its concerns about the devastating
> >> effects that the Russian military offensive has on their
> >> country and on the free and peaceful scientific, cultural,
> >> and economic cooperation amongst peoples
> >> ___
> >> Quantum ESPRESSO is supported by MaX (www.max-centre.eu)
> >> users mailing list users@lists.quantum-espresso.org
> >> https://lists.quantum-espresso.org/mailman/listinfo/users
> >>
> >>
> >> ___
> >> The Quantum ESPRESSO community stands by the

[QE-users] Regarding bands

2022-04-28 Thread Satyasiban Dash ph19d005 
Dear Users
 I have been trying to calculate a heterostructure with a slab model. I
have followed most of the examples given in the forum and tried it still I
am getting a metallic band structure. I have used the K-path generation
tool provided in "material project" website  to generate k-path. I have
given the scf and bands.in file as attached files. Please have a look.
Experimentally this system has a wide band gap.


Thanks.
Satya
Research Scholar
IIT Madras.


scf.in
Description: Binary data


job576185.pw.in
Description: Binary data
___
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Re: [QE-users] Regarding bands

2022-04-28 Thread Giovanni Cantele 
Dear Satya,

it is not that easy (at least for me) to provide an answer to your question 
using the data you have provided. Maybe the output files (of scf and bands) and 
a plot of your band structure might help to infer if there is any issue in your 
calculation.

However, before wondering whether you get a metal whereas experiments measure a 
gap, you should also check that you are simulating a system that is as close as 
possible to the experimental one (in terms of thickness and/or surface 
orientation of both ZnO and Si, and so on). As far as the atomic positions are 
concerned, they look reasonable. It seems (if I’m not wrong) that you are 
trying to match a Si(100) surface with a ZnO(0001) surface, aren’t you? Is this 
what you expect?

Giovanni

-- 

Giovanni Cantele, PhD
CNR-SPIN
c/o Dipartimento di Fisica
Universita' di Napoli "Federico II"
Complesso Universitario M. S. Angelo - Ed. 6
Via Cintia, I-80126, Napoli, Italy
e-mail: giovanni.cant...@spin.cnr.it
Phone: +39 081 676910
Skype contact: giocan74

ResearcherID: http://www.researcherid.com/rid/A-1951-2009
Web page: https://sites.google.com/view/giovanni-cantele/home


> On 28 Apr 2022, at 07:09, Satyasiban Dash ph19d005 
>  wrote:
> 
> Dear Users
>  I have been trying to calculate a heterostructure with a slab model. I have 
> followed most of the examples given in the forum and tried it still I am 
> getting a metallic band structure. I have used the K-path generation tool 
> provided in "material project" website  to generate k-path. I have given the 
> scf and bands.in  file as attached files. Please have a 
> look. Experimentally this system has a wide band gap.
> 
> 
> Thanks.
> Satya
> Research Scholar
> IIT Madras.
> ___
> The Quantum ESPRESSO community stands by the Ukrainian
> people and expresses its concerns about the devastating
> effects that the Russian military offensive has on their
> country and on the free and peaceful scientific, cultural,
> and economic cooperation amongst peoples
> ___
> Quantum ESPRESSO is supported by MaX (www.max-centre.eu)
> users mailing list users@lists.quantum-espresso.org
> https://lists.quantum-espresso.org/mailman/listinfo/users

___
The Quantum ESPRESSO community stands by the Ukrainian
people and expresses its concerns about the devastating
effects that the Russian military offensive has on their
country and on the free and peaceful scientific, cultural,
and economic cooperation amongst peoples
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users mailing list users@lists.quantum-espresso.org
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Re: [QE-users] Regarding bands

2022-04-28 Thread Satyasiban Dash ph19d005 
Yes . Thank you for the clarification. I am trying to match (0001) surface.
But I have observed upon relaxing ZnO loosing its symmetry and this may be
due to the polar surfaces but experimentally we do observe a band gap. I
have also tried dipole correction but results are same. But if I remove Si
its giving a gap. Is there anyway to reproduce it with Si (001).

On Thu, 28 Apr, 2022, 4:55 pm Giovanni Cantele, <
giovanni.cant...@spin.cnr.it> wrote:

> Dear Satya,
>
> it is not that easy (at least for me) to provide an answer to your
> question using the data you have provided. Maybe the output files (of scf
> and bands) and a plot of your band structure might help to infer if there
> is any issue in your calculation.
>
> However, before wondering whether you get a metal whereas experiments
> measure a gap, you should also check that you are simulating a system that
> is as close as possible to the experimental one (in terms of thickness
> and/or surface orientation of both ZnO and Si, and so on). As far as the
> atomic positions are concerned, they look reasonable. It seems (if I’m not
> wrong) that you are trying to match a Si(100) surface with a ZnO(0001)
> surface, aren’t you? Is this what you expect?
>
> Giovanni
>
> --
>
> Giovanni Cantele, PhD
> CNR-SPIN
> c/o Dipartimento di Fisica
> Universita' di Napoli "Federico II"
> Complesso Universitario M. S. Angelo - Ed. 6
> Via Cintia, I-80126, Napoli, Italy
> e-mail: giovanni.cant...@spin.cnr.it 
> Phone: +39 081 676910
> Skype contact: giocan74
>
> ResearcherID: http://www.researcherid.com/rid/A-1951-2009
> Web page: https://sites.google.com/view/giovanni-cantele/home
>
>
> On 28 Apr 2022, at 07:09, Satyasiban Dash ph19d005 <
> ph19d...@smail.iitm.ac.in> wrote:
>
> Dear Users
>  I have been trying to calculate a heterostructure with a slab model. I
> have followed most of the examples given in the forum and tried it still I
> am getting a metallic band structure. I have used the K-path generation
> tool provided in "material project" website  to generate k-path. I have
> given the scf and bands.in file as attached files. Please have a look.
> Experimentally this system has a wide band gap.
>
>
> Thanks.
> Satya
> Research Scholar
> IIT Madras.
> ___
> The Quantum ESPRESSO community stands by the Ukrainian
> people and expresses its concerns about the devastating
> effects that the Russian military offensive has on their
> country and on the free and peaceful scientific, cultural,
> and economic cooperation amongst peoples
> ___
> Quantum ESPRESSO is supported by MaX (www.max-centre.eu)
> users mailing list users@lists.quantum-espresso.org
> https://lists.quantum-espresso.org/mailman/listinfo/users
>
>
> ___
> The Quantum ESPRESSO community stands by the Ukrainian
> people and expresses its concerns about the devastating
> effects that the Russian military offensive has on their
> country and on the free and peaceful scientific, cultural,
> and economic cooperation amongst peoples
> ___
> Quantum ESPRESSO is supported by MaX (www.max-centre.eu)
> users mailing list users@lists.quantum-espresso.org
> https://lists.quantum-espresso.org/mailman/listinfo/users
___
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people and expresses its concerns about the devastating
effects that the Russian military offensive has on their
country and on the free and peaceful scientific, cultural,
and economic cooperation amongst peoples
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Re: [QE-users] Regarding bands

2022-04-28 Thread Stefano Baroni 


> On 28 Apr 2022, at 14:27, Giuseppe Mattioli  
> wrote:
> 
> 
> Dear Satya
> 
> …
> 4) Such a strongly polar surface in contact with a non-polar Si surface may 
> induce a huge interfacial charge transfer, even enhanced by delocalization 
> errors mentioned above, or can lead to significant shifts of band edges, 
> yielding a metallic character of the semiconductor junction.

BRAVO! The most relevant remark, IMHO. SB

___
Stefano Baroni, Trieste -- http://stefano.baroni.me
> 
> HTH
> Giuseppe
> 
> Quoting Satyasiban Dash ph19d005 :
> 
>> Yes . Thank you for the clarification. I am trying to match (0001) surface.
>> But I have observed upon relaxing ZnO loosing its symmetry and this may be
>> due to the polar surfaces but experimentally we do observe a band gap. I
>> have also tried dipole correction but results are same. But if I remove Si
>> its giving a gap. Is there anyway to reproduce it with Si (001).
>>> On Thu, 28 Apr, 2022, 4:55 pm Giovanni Cantele, <
>>> giovanni.cant...@spin.cnr.it> wrote:
>>> Dear Satya,
>>> it is not that easy (at least for me) to provide an answer to your
>>> question using the data you have provided. Maybe the output files (of scf
>>> and bands) and a plot of your band structure might help to infer if there
>>> is any issue in your calculation.
>>> However, before wondering whether you get a metal whereas experiments
>>> measure a gap, you should also check that you are simulating a system that
>>> is as close as possible to the experimental one (in terms of thickness
>>> and/or surface orientation of both ZnO and Si, and so on). As far as the
>>> atomic positions are concerned, they look reasonable. It seems (if I’m not
>>> wrong) that you are trying to match a Si(100) surface with a ZnO(0001)
>>> surface, aren’t you? Is this what you expect?
>>> Giovanni
>>> --
>>> Giovanni Cantele, PhD
>>> CNR-SPIN
>>> c/o Dipartimento di Fisica
>>> Universita' di Napoli "Federico II"
>>> Complesso Universitario M. S. Angelo - Ed. 6
>>> Via Cintia, I-80126, Napoli, Italy
>>> e-mail: giovanni.cant...@spin.cnr.it 
>>> Phone: +39 081 676910
>>> Skype contact: giocan74
>>> ResearcherID: http://www.researcherid.com/rid/A-1951-2009
>>> Web page: https://sites.google.com/view/giovanni-cantele/home
>>> On 28 Apr 2022, at 07:09, Satyasiban Dash ph19d005 <
>>> ph19d...@smail.iitm.ac.in> wrote:
>>> Dear Users
>>> I have been trying to calculate a heterostructure with a slab model. I
>>> have followed most of the examples given in the forum and tried it still I
>>> am getting a metallic band structure. I have used the K-path generation
>>> tool provided in "material project" website  to generate k-path. I have
>>> given the scf and bands.in file as attached files. Please have a look.
>>> Experimentally this system has a wide band gap.
>>> Thanks.
>>> Satya
>>> Research Scholar
>>> IIT Madras.
>>> ___
>>> The Quantum ESPRESSO community stands by the Ukrainian
>>> people and expresses its concerns about the devastating
>>> effects that the Russian military offensive has on their
>>> country and on the free and peaceful scientific, cultural,
>>> and economic cooperation amongst peoples
>>> ___
>>> Quantum ESPRESSO is supported by MaX (www.max-centre.eu)
>>> users mailing list users@lists.quantum-espresso.org
>>> https://lists.quantum-espresso.org/mailman/listinfo/users
>>> ___
>>> The Quantum ESPRESSO community stands by the Ukrainian
>>> people and expresses its concerns about the devastating
>>> effects that the Russian military offensive has on their
>>> country and on the free and peaceful scientific, cultural,
>>> and economic cooperation amongst peoples
>>> ___
>>> Quantum ESPRESSO is supported by MaX (www.max-centre.eu)
>>> users mailing list users@lists.quantum-espresso.org
>>> https://lists.quantum-espresso.org/mailman/listinfo/users
> 
> 
> 
> GIUSEPPE MATTIOLI
> CNR - ISTITUTO DI STRUTTURA DELLA MATERIA
> Via Salaria Km 29,300 - C.P. 10
> I-00015 - Monterotondo Scalo (RM)
> Mob (*preferred*) +39 373 7305625
> Tel + 39 06 90672342 - Fax +39 06 90672316
> E-mail: 
> 
> ___
> The Quantum ESPRESSO community stands by the Ukrainian
> people and expresses its concerns about the devastating
> effects that the Russian military offensive has on their
> country and on the free and peaceful scientific, cultural,
> and economic cooperation amongst peoples
> ___
> Quantum ESPRESSO is supported by MaX (www.max-centre.eu)
> users mailing list users@lists.quantum-espresso.org
> https://lists.quantum-espresso.org/mailman/listinfo/users
___
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Re: [QE-users] Regarding bands

2022-04-28 Thread Giovanni Cantele 
Dipole correction might certainly being a point, also given that you are 
considering a polar system. 

So you could try to share in/out files including dipole correction.

Moreover, you should also try to understand whether or not the metallicity you 
find is a spurious effect or not. 
Try, for example, to make a plot of the averaged potential along direction 
orthogonal to the heterostructure, to see if it looks reasonable. 
Also you could make charge transfer plots, again to guess if they provide at 
least reasonable results or unphysical patterns.
Another point: are you SURE that you have correctly matched the Si surface to 
the ZnO? Indeed, you said that after removing the ZnO, you find a gap. Could it 
be that metallicity is induced by “surface” (in this case “interface”) states 
of Si(100)? Depending on its reconstruction, Si(100) can show surface states 
with different or no gap between occupied and unoccupied states, as far as I 
remember.

Giovanni

> On 28 Apr 2022, at 13:38, Satyasiban Dash ph19d005 
>  wrote:
> 
> Yes . Thank you for the clarification. I am trying to match (0001) surface. 
> But I have observed upon relaxing ZnO loosing its symmetry and this may be 
> due to the polar surfaces but experimentally we do observe a band gap. I have 
> also tried dipole correction but results are same. But if I remove Si its 
> giving a gap. Is there anyway to reproduce it with Si (001).
> 
> On Thu, 28 Apr, 2022, 4:55 pm Giovanni Cantele,  > wrote:
> Dear Satya,
> 
> it is not that easy (at least for me) to provide an answer to your question 
> using the data you have provided. Maybe the output files (of scf and bands) 
> and a plot of your band structure might help to infer if there is any issue 
> in your calculation.
> 
> However, before wondering whether you get a metal whereas experiments measure 
> a gap, you should also check that you are simulating a system that is as 
> close as possible to the experimental one (in terms of thickness and/or 
> surface orientation of both ZnO and Si, and so on). As far as the atomic 
> positions are concerned, they look reasonable. It seems (if I’m not wrong) 
> that you are trying to match a Si(100) surface with a ZnO(0001) surface, 
> aren’t you? Is this what you expect?
> 
> Giovanni
> 
> -- 
> 
> Giovanni Cantele, PhD
> CNR-SPIN
> c/o Dipartimento di Fisica
> Universita' di Napoli "Federico II"
> Complesso Universitario M. S. Angelo - Ed. 6
> Via Cintia, I-80126, Napoli, Italy
> e-mail: giovanni.cant...@spin.cnr.it 
> Phone: +39 081 676910
> Skype contact: giocan74
> 
> ResearcherID: http://www.researcherid.com/rid/A-1951-2009 
> 
> Web page: https://sites.google.com/view/giovanni-cantele/home 
> 
> 
> 
>> On 28 Apr 2022, at 07:09, Satyasiban Dash ph19d005 
>> mailto:ph19d...@smail.iitm.ac.in>> wrote:
>> 
>> Dear Users
>>  I have been trying to calculate a heterostructure with a slab model. I have 
>> followed most of the examples given in the forum and tried it still I am 
>> getting a metallic band structure. I have used the K-path generation tool 
>> provided in "material project" website  to generate k-path. I have given the 
>> scf and bands.in  file as attached files. Please have a 
>> look. Experimentally this system has a wide band gap.
>> 
>> 
>> Thanks.
>> Satya
>> Research Scholar
>> IIT Madras.
>> http://scf.in/>>> >___
>> The Quantum ESPRESSO community stands by the Ukrainian
>> people and expresses its concerns about the devastating
>> effects that the Russian military offensive has on their
>> country and on the free and peaceful scientific, cultural,
>> and economic cooperation amongst peoples
>> ___
>> Quantum ESPRESSO is supported by MaX (www.max-centre.eu 
>> )
>> users mailing list users@lists.quantum-espresso.org 
>> 
>> https://lists.quantum-espresso.org/mailman/listinfo/users 
>> 
> ___
> The Quantum ESPRESSO community stands by the Ukrainian
> people and expresses its concerns about the devastating
> effects that the Russian military offensive has on their
> country and on the free and peaceful scientific, cultural,
> and economic cooperation amongst peoples
> ___
> Quantum ESPRESSO is supported by MaX (www.max-centre.eu 
> )
> users mailing list users@lists.quantum-espresso.org 
> 
> https://lists.quantum-espresso.org/mailman/listinfo/users 
> ___
>

Re: [QE-users] Error - unknown cell_dofree ibrav

2022-04-28 Thread Vahid Askarpour 
Congratulations for passing Paolo’s test of the functionality of the mailing 
list.

Cheers,
Vahid

Vahid Askarpour
Department of physics and atmospheric science
Dalhousie University
Halifax, NS
CANADA

On Apr 28, 2022, at 6:50 AM, remya ud 
mailto:remyau...@gmail.com>> wrote:

CAUTION: The Sender of this email is not from within Dalhousie.
Dear all,
Finally, the 'unknown cell_dofree 'ibrav ' error that occurred during VC 
relaxation calculation is solved. Initially, I installed pw.x of the old 
version. Recently, Q.E.7.0 is installed. But the program was running on the 
previous version.
Sorry for the inconvenience.
thank you

On Thu, Apr 28, 2022 at 10:46 AM remya ud 
mailto:remyau...@gmail.com>> wrote:
Dear all,
I am trying to do the vc_relax calculation of Si. But it cracked with an error
task # 0
 from  init_dofree: error # 1
  unknown cell_dofree ibrav

I am using the 7.0 version of the Quantum espresso. And also checked in 
Modules/cell_base.f90 as suggested by the mailing list. When I tried with 
'all', 'shape', and 'volume', they didn't show similar errors. Kindly correct 
me where I went wrong in the calculation since 'ibrav' is working for others.

Input file is

calculation ='vc-relax'
prefix = 'si'
outdir = './ outdir'
pseudo_dir = '.'
etot_conv_thr = 1e-5
forc_conv_thr = 1e-4
 /

 
ibrav = 2
celldm(1) = 14
nat = 2
ntyp = 1
ecutwfc = 30
 /

 
   conv_thr=1.e-7
 /

/

   cell_dofree='ibrav'
/
ATOMIC_SPECIES
 Si  28.0855  Si.pbe-n-rrkjus_psl.1.0.0.UPF

ATOMIC_POSITIONS alat
 Si 0.00 0.00 0.00 0 0 0
 Si 0.25 0.25 0.25 0 0 0

K_POINTS automatic
  4 4 4 0 0 0


The  subroutine start with
SUBROUTINE init_dofree ( cell_dofree )
 !! Set constraints on cell dynamics/optimization

 CHARACTER(LEN=*), INTENT(IN) :: cell_dofree
 CHARACTER(LEN=80) :: cell_dofree_

 IF(cell_dofree(1:5) == 'ibrav') THEN
   iforceh = 1
   enforce_ibrav = .true.
   IF(cell_dofree(6:6)=="+")THEN
 cell_dofree_ = cell_dofree(7:)
   ELSE
 cell_dofree_="default"
   ENDIF
 ELSE
   cell_dofree_ = cell_dofree
 ENDIF

 SELECT CASE ( TRIM( cell_dofree_ ) )

CASE ( 'all', 'default', '' )
  iforceh = 1
!CASE ('ibrav')
  !iforceh = 1
  !enforce_ibrav = .true.
CASE ( 'shape' )
  iforceh = 1
  fix_volume = .true.
Kindly suggest some solution to solve this.



--
Remya. U. D
Research Scholar
Intermetallics and Nonlinear Optical Lab
National Institute of Technology
Tiruchirappalli, Tamil Nadu
India




--
Remya. U. D
Research Scholar
Intermetallics and Nonlinear Optical Lab
National Institute of Technology
Tiruchirappalli, Tamil Nadu
India
___
The Quantum ESPRESSO community stands by the Ukrainian
people and expresses its concerns about the devastating
effects that the Russian military offensive has on their
country and on the free and peaceful scientific, cultural,
and economic cooperation amongst peoples
___
Quantum ESPRESSO is supported by MaX 
(www.max-centre.eu)
users mailing list 
users@lists.quantum-espresso.org
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___
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people and expresses its concerns about the devastating
effects that the Russian military offensive has on their
country and on the free and peaceful scientific, cultural,
and economic cooperation amongst peoples
___
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users mailing list users@lists.quantum-espresso.org
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Re: [QE-users] Regarding bands

2022-04-28 Thread Giuseppe Mattioli 


Dear Satya

Like Giovanni, I also don't know why you don't obtain what you expect.  
But I want to offer my own penny to the discussion.


1) Due to the well known effect of delocalization errors in GGA-DFT,  
the band gap of Si is generally reduced to around 0.6 eV. The  
reduction involves both the lowering of the conduction band potential  
and the raising of the valence band potential. In the case of ZnO you  
have a strongly curved conduction band around the minimum at Gamma,  
which is not affected by delocalization errors, and a very problematic  
valence band, in which the interaction between the narrow O 2p and Zn  
3d contributions may raise the valence band maximum by more than 2 eV,  
shrinking the band gap to less than 1 eV in bulk ZnO.


2) First of all, therefore, I would check *in the same supercell* if  
isolated Si and isolated ZnO slabs envisage a metallic character of  
the junction due to the unsymmetrical band gap underestimation of the  
two parts.


3) The most stable ZnO surface is (10-10), not 0001 (or its 000-1  
counterpart having reverse polarity). The polar surfaces of ZnO are  
tricky to simulate as slabs due to the strong polarity of the Zn-O  
bond. In the past, I obtained some weird layered hexagonal structure  
similar to BN! I suppose that the choice of (0001) is purposeful. If  
it is not, try to reconsider your choice.


4) Such a strongly polar surface in contact with a non-polar Si  
surface may induce a huge interfacial charge transfer, even enhanced  
by delocalization errors mentioned above, or can lead to significant  
shifts of band edges, yielding a metallic character of the  
semiconductor junction.


HTH
Giuseppe

Quoting Satyasiban Dash ph19d005 :


Yes . Thank you for the clarification. I am trying to match (0001) surface.
But I have observed upon relaxing ZnO loosing its symmetry and this may be
due to the polar surfaces but experimentally we do observe a band gap. I
have also tried dipole correction but results are same. But if I remove Si
its giving a gap. Is there anyway to reproduce it with Si (001).

On Thu, 28 Apr, 2022, 4:55 pm Giovanni Cantele, <
giovanni.cant...@spin.cnr.it> wrote:


Dear Satya,

it is not that easy (at least for me) to provide an answer to your
question using the data you have provided. Maybe the output files (of scf
and bands) and a plot of your band structure might help to infer if there
is any issue in your calculation.

However, before wondering whether you get a metal whereas experiments
measure a gap, you should also check that you are simulating a system that
is as close as possible to the experimental one (in terms of thickness
and/or surface orientation of both ZnO and Si, and so on). As far as the
atomic positions are concerned, they look reasonable. It seems (if I’m not
wrong) that you are trying to match a Si(100) surface with a ZnO(0001)
surface, aren’t you? Is this what you expect?

Giovanni

--

Giovanni Cantele, PhD
CNR-SPIN
c/o Dipartimento di Fisica
Universita' di Napoli "Federico II"
Complesso Universitario M. S. Angelo - Ed. 6
Via Cintia, I-80126, Napoli, Italy
e-mail: giovanni.cant...@spin.cnr.it 
Phone: +39 081 676910
Skype contact: giocan74

ResearcherID: http://www.researcherid.com/rid/A-1951-2009
Web page: https://sites.google.com/view/giovanni-cantele/home


On 28 Apr 2022, at 07:09, Satyasiban Dash ph19d005 <
ph19d...@smail.iitm.ac.in> wrote:

Dear Users
 I have been trying to calculate a heterostructure with a slab model. I
have followed most of the examples given in the forum and tried it still I
am getting a metallic band structure. I have used the K-path generation
tool provided in "material project" website  to generate k-path. I have
given the scf and bands.in file as attached files. Please have a look.
Experimentally this system has a wide band gap.


Thanks.
Satya
Research Scholar
IIT Madras.
___
The Quantum ESPRESSO community stands by the Ukrainian
people and expresses its concerns about the devastating
effects that the Russian military offensive has on their
country and on the free and peaceful scientific, cultural,
and economic cooperation amongst peoples
___
Quantum ESPRESSO is supported by MaX (www.max-centre.eu)
users mailing list users@lists.quantum-espresso.org
https://lists.quantum-espresso.org/mailman/listinfo/users


___
The Quantum ESPRESSO community stands by the Ukrainian
people and expresses its concerns about the devastating
effects that the Russian military offensive has on their
country and on the free and peaceful scientific, cultural,
and economic cooperation amongst peoples
___
Quantum ESPRESSO is supported by MaX (www.max-centre.eu)
users mailing list users@lists.quantum-espresso.org
https://lists.quantum-espresso.org/mailman/listinfo/users




GIUSEPPE MATTIOLI
CNR - ISTITUTO DI STRUTTURA DELLA