Hello
In any case, just to post it in this thread.
Fractional charge H pseudos for PZ-LDA can be found at this page:
http://www.quantum-espresso.org/pseudopotentials/original-qe-pp-library/h
they have names like H.pz-vbc_050.UPF
<http://www.quantum-espresso.org/upf_files/H.pz-vbc_050.UPF> and analogous.
have a nice day
Pietro
On 08/08/2018 16:39, Matthieu Fortin-Deschênes wrote:
Thanks for the info. I'll take a look at those papers.
Matthieu
Giuseppe Mattioli <[email protected]> a écrit :
I believe fractional charge H atoms would not be useful for these
kinds of materials. Right?
I suppose you are right. I can only suggest you to double check the
results and to carefully compare with experimental results obtained
on real systems. I cited C-diamond, which is "akin" to Si and Ge,
because surface hydrogenation induce a large upward shift of both
valence and conduction bands, measured by ARPES and compared with DFT
calculations here: Phys. Rev. B 94, 045307 (2016)
Surface or interstitial H is a well known dopant in semiconductors.
Among tons of papers (I'm ashamed to cite mine :-)) I can suggest the
classical Van de Walle Nature paper on universal alignment of H
(Nature 423, 626, 2003)
HTH
Giuseppe
Quoting Matthieu Fortin-Deschênes
<[email protected]>:
Thanks Giuseppe,
I actually want to passivate the bottom of Si and Ge surfaces, as
well as one edge of a 2D nanoribbon (antimonene).
I believe fractional charge H atoms would not be useful for these
kinds of materials. Right?
I was not aware of this strong dopant effect, but I'd be interested
in reading more about it if you have any reference to suggest.
Thank you,
Matthieu
Giuseppe Mattioli <[email protected]> a écrit :
Dear Matthieu
I don't know which surface you want to passivate, but remember that
H can also have a strong dopant effect on surfaces (e.g., a large
upward shift of both band edges, which has been measured on
C-diamond). Therefore, I used to passivate the unreconstructed end
of III-V slabs with *pseudo* H atoms, having fractional charge
which simulate a bulk environment surrounding the bottom layer of
the slab. They used to be in the online library but they are not
anymore (maybe for good reasons which I don't know). If you want to
try I can send you the UPF files. They are NC VBC pseudopotentials
which should not require more than ecutwfc=40: after all you are
not interested in structural rearrangement but you only need
electronic passivation of surface states.
HTH
Giuseppe
Quoting Matthieu Fortin-Deschênes
<[email protected]>:
Hi all,
I want to use hydrogen to passivate the bottom surface of a
surface slab. However, I notice that H PPs usually require a high
ecutwfc, which restricts the size of the system I can consider.
Are there any PPs with lower required ecutwfc available for that
purpose?
And would this negatively effect the accuracy of the calculations
on the other side of the surface slab?
Thank you,
Matthieu Fortin-Deschênes
Polytechnique Montréal
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GIUSEPPE MATTIOLI
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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: <[email protected]>
_______________________________________________
users mailing list
[email protected]
https://lists.quantum-espresso.org/mailman/listinfo/users
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