[QE-users] Regarding bands

[Stefano Baroni]

> On 28 Apr 2022, at 14:27, Giuseppe Mattioli <giuseppe.mattioli at ism.cnr.it> 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 <ph19d005 at smail.iitm.ac.in>:
> 
>> 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.cantele at 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.cantele at spin.cnr.it <giovanni.cantele at 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 <
>>> ph19d005 at 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.
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> 
> 
> 
> GIUSEPPE MATTIOLI
> CNR - ISTITUTO DI STRUTTURA DELLA MATERIA
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> 
> _______________________________________________
> 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 at lists.quantum-espresso.org
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