[QE-users] Soft Hydrogen Pseudopotentials

[Pietro Delugas]

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 <giuseppe.mattioli at ism.cnr.it> 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 
>> <matthieu.fortin-deschenes at polymtl.ca>:
>>
>>> 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 <giuseppe.mattioli at ism.cnr.it> 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 
>>>> <matthieu.fortin-deschenes at polymtl.ca>:
>>>>
>>>>> 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
>>>>>
>>>>> _______________________________________________
>>>>> users mailing list
>>>>> users at lists.quantum-espresso.org
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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: <giuseppe.mattioli at ism.cnr.it>
>>>>
>>>> _______________________________________________
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>>>
>>>
>>>
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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: <giuseppe.mattioli at ism.cnr.it>
>>
>> _______________________________________________
>> users mailing list
>> users at lists.quantum-espresso.org
>> https://lists.quantum-espresso.org/mailman/listinfo/users
>
>
>
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