For ab inito calculations check out eg:
https://doi.org/10.1021/jp508880y
Am 21.12.2019 um 09:25 schrieb Gavin Abo:
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
<pbl...@theochem.tuwien.ac.at <mailto:pbl...@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....@gmail.com
<mailto:onnyorup....@gmail.com>
> <mailto:onnyorup....@gmail.com <mailto:onnyorup....@gmail.com>>>
> Date: Wed, Dec 4, 2019 at 2:31 PM
> Subject: Band Edge position
> To: A Mailing list for WIEN2k users
<wien@zeus.theochem.tuwien.ac.at
<mailto:wien@zeus.theochem.tuwien.ac.at>
> <mailto:wien@zeus.theochem.tuwien.ac.at
<mailto:wien@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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--
--------------------------------------------------------------------------
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Phone: +43-1-58801-165300 FAX: +43-1-58801-165982
Email: bl...@theochem.tuwien.ac.at
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WWW:
http://www.imc.tuwien.ac.at/tc_blaha-------------------------------------------------------------------------
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Best regards,
------------------------------------------------------------
Subhasis Panda
Assistant Professor
Department of Physics
National Institute of Technology Silchar
Assam, India - 788010.
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Phone: +43-1-58801-165300 FAX: +43-1-58801-165982
Email: bl...@theochem.tuwien.ac.at WIEN2k: http://www.wien2k.at
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