[QE-users] Magnetism of holmium

[Lorenzo Paulatto]

> Lorenzo - sure, but why? Wentzcovitch pseudopotential are more accurate,
> and they require roughly ~40Ry.
> 

I've tried both set at the beginning, but I could not get reliable 
results with the Wentzcovitch (W) ones. The pslibrary one are a big 
pain, a constant barely tolerable  pain. The W ones are (in my 
experience) less of a pain until they work, but sometimes the total 
energy went completely off, as if there was some kind of ghost state.

I think there is just no easy way to treat rare earth metals.

>              nicola
> 
>> -- 
>> Lorenzo Paulatto
>> Written on a virtual keyboard with real fingers
>>
>> On Mon, 1 Oct 2018, 18:28 Nicola Marzari, <nicola.marzari at epfl.ch 
>> <mailto:nicola.marzari at epfl.ch>> wrote:
>>
>>
>>
>>     Dear Martin,
>>
>>     we tested a couple of pseudo libraries with the f frozen, but apart
>>     from
>>     La they do not work that well in general. As mentioned by 
>> Christopher,
>>     you want the f.
>>
>>     Here are a few tests:
>>     https://www.materialscloud.org/discover/sssp/plot/efficiency/Ho
>>
>>     and if you eg brose the provennce tree for the Ho US pslibrary 1.0
>>     until you get to a PWscf calculation:
>>
>>     
>> https://www.materialscloud.org/explore/sssp/details/f2383960-43b6-4bf6-b080-b49e43c6ce12?nodeType=CALCULATION 
>>
>>
>>     you can see that the pseudo tested is
>>     Ho.pbe-spdfn-rrkjus_psl.1.0.0.UPF
>>
>>     I would tend to recommend the Wentzocvitch series, but it's true that
>>     all rare earths are rarely tested. In addition, they have strong
>>     multiconfigurational character, so standard LDA/GGA/GGA+U/HSE
>>     DFT doesn't do that well.
>>
>>                                      nicola
>>
>>
>>
>>
>>     On 01/10/2018 10:30, Ing. Martin Matas wrote:
>>      > Dear experts,
>>      >
>>      > I appreciate that many new ultrasoft pseudopotentials for rare
>>     earths by Andrea Dal Corso have recently appeared on QE homepage. I
>>     performed calculations with a 2-atom primitive cell of metal holmium
>>     using Ho.pbe-spdn-rrkjus_psl.1.0.0.UPF, with both ferromagnetic and
>>     antiferromagnetic starting configurations.
>>      >
>>      > The resulting magnetization is always zero, not depending on
>>     calculation parameters (like starting_magnetization, occupation type
>>     and degauss, or energy cutoffs). However, exactly the same
>>     calculations using a norm-conserving holmium pseudopotential give
>>     results with a non-zero magnetization what I consider correct since
>>     holmium at zero temperature is ferromagnetic.
>>      >
>>      > Did anyone test these new ultrasoft pseudopotentials in this way
>>     and is there a way how to get magnetically correct results using 
>> them?
>>      > Thanks a lot.
>>      >
>>      > Martin Matas
>>      > PhD student
>>      > University of West Bohemia
>>      > Czech Republic
>>      >
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>>
>>
>>     --     
>> ----------------------------------------------------------------------
>>     Prof Nicola Marzari, Chair of Theory and Simulation of Materials, 
>> EPFL
>>     Director, National Centre for Competence in Research NCCR MARVEL, 
>> EPFL
>>     http://theossrv1.epfl.ch/Main/Contact 
>> http://nccr-marvel.ch/en/project
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> 
> 

-- 
Lorenzo Paulatto - Paris