[Wien] Fwd: Fwd: Band Edge position
Gavin Abo
gsabo at crimson.ua.edu
Sat Dec 21 09:25:13 CET 2019
You might have a look at Eqn (6) in [1]. It looks like that is used as
the E_CB equation in [2]. Look in [3] how pHzpc - pH = 0 in Eqn (1)
simplifies to Eqn (2).
There are three methods to determine band edge positions. Second method
of first principle has large discrepancies between calculated and
measured values. Third method of simple approach of Butler and Ginley
used in [1,2] gives reasonable results [4], which validity was
demonstrated on 11 oxides [5,6]. The method popularized by the paper of
Xu and Schoonen [7]. The absolute electronegativity changes with the
atoms and its elements [8,9].
[1] https://doi.org/10.2138/am-2000-0416
[2] http://www.rsc.org/suppdata/cp/c4/c4cp03494e/c4cp03494e1.pdf
[3] http://www.rsc.org/suppdata/c7/cy/c7cy00393e/c7cy00393e1.pdf
[4] https://doi.org/10.1016/j.jksus.2014.06.002
[5]
https://pubs.rsc.org/en/content/articlelanding/2014/CP/c3cp54589j#!divAbstract
[6] https://doi.org/10.1063/1.5041784
[7] http://www.rsc.org/suppdata/cc/c2/c2cc31398g/c2cc31398g.pdf
[8] https://doi.org/10.1016/j.ceramint.2018.01.064
[9]
https://www.researchgate.net/post/How_can_I_calculate_absolute_electronegativity_of_CuAl2O4
On 12/20/2019 9:58 AM, Subhasis Panda wrote:
>
>
> ---
>
> Dear Experts,
>
> I wanted to calculate the absolute band edge energies for RbPbI_3
> compound only (not any interface like RbPbI3 and TiO2 interface) in
> the orthorhombic phase. As already suggested, it's a computationally
> costly work and we don't have enough computational facility also in
> our institute. I was searching in the internet and got the following
> information. Looking forward to your expert opinion.
>
>
> In the following reference, using Eqn 1(a) & (b) can we estimate that?
> It requires absolute electronegativity of the semiconductor and the
> band gap.
> https://doi.org/10.2138/am-2000-0416
>
> whereas in the following reference, the expressions are a little
> different.
> http://www.rsc.org/suppdata/cp/c4/c4cp03494e/c4cp03494e1.pdf
>
> Are these two expressions referring to the same thing? If not which
> one shall we use. I've one more query, does absolute electronegativity
> of a material (semiconductor) changes with its crystal structure type
> (like bcc, fcc)?
>
> Looking forward to your reply.
> Thank you and best regards
> Subhasis
>
>
> On Fri, Dec 6, 2019 at 12:57 AM Peter Blaha
> <pblaha at theochem.tuwien.ac.at <mailto:pblaha at theochem.tuwien.ac.at>>
> wrote:
>
> This is not such a simple task. You will have to create a supercell
> simulating the interface between the two materials.
>
> The answer can change depending how you form the interface.
> Furthermore
> this can be a complicated task, as the periodicity must fit and
> one has
> to test/define various surfaces/interfaces (except if 2 materials
> happen
> to grow nicely epitaxically).
>
> A simpler but much less accurate approach is to do 2 independent
> surface
> slab calculations with sufficient vacuum. From the difference of
> EF and
> the coulomb potential in the middle of the vacuum (:VZERO) you get an
> absolute band edge (actually this is the work function in a solid).
> However, this method neglects band bending, charge transfer or dipole
> formations at the interface, which could completely spoil the answer.
>
> Am 05.12.2019 um 11:27 schrieb Subhasis Panda:
> >
> >
> > ---------- Forwarded message ---------
> > From: *Subhasis Panda* <onnyorup.iit at gmail.com
> <mailto:onnyorup.iit at gmail.com>
> > <mailto:onnyorup.iit at gmail.com <mailto:onnyorup.iit at gmail.com>>>
> > Date: Wed, Dec 4, 2019 at 2:31 PM
> > Subject: Band Edge position
> > To: A Mailing list for WIEN2k users
> <wien at zeus.theochem.tuwien.ac.at
> <mailto:wien at zeus.theochem.tuwien.ac.at>
> > <mailto:wien at zeus.theochem.tuwien.ac.at
> <mailto:wien at zeus.theochem.tuwien.ac.at>>>
> >
> >
> >
> > Dear experts,
> > How can I estimate the absolute band edge position (CB/VB) of a
> > semiconductor using Wien2k?
> > The attached figure is what I'm trying to get.
> > Looking forward to your kind help.
> >
> > --
> >
> >
> >
> > Best regards,
> > ------------------------------------------------------------
> > Subhasis Panda
> > Assistant Professor
> > Department of Physics
> > National Institute of Technology Silchar
> > Assam, India - 788010.
> >
> > -------------------------------------------------------------
> >
> >
> > --
> >
> >
> >
> > Best regards,
> > ------------------------------------------------------------
> > Subhasis Panda
> > Assistant Professor
> > Department of Physics
> > National Institute of Technology Silchar
> > Assam, India - 788010.
> >
> > -------------------------------------------------------------
> >
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>
> --
> --------------------------------------------------------------------------
> Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
> Phone: +43-1-58801-165300 FAX: +43-1-58801-165982
> Email: blaha at theochem.tuwien.ac.at
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> WWW:
> http://www.imc.tuwien.ac.at/tc_blaha-------------------------------------------------------------------------
>
>
>
>
> --
>
>
>
> Best regards,
> ------------------------------------------------------------
> Subhasis Panda
> Assistant Professor
> Department of Physics
> National Institute of Technology Silchar
> Assam, India - 788010.
>
> -------------------------------------------------------------
>
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