[Wien] confusion regarding band structure of Graphene
xavier rocquefelte
xavier.rocquefelte at univ-rennes1.fr
Fri Dec 30 18:27:18 CET 2022
OK :) Using HSE06 allows to do not have to do correction.
But you must be aware that you are in the error bar of the method. It is
why I was surprised by this calculation (between materials used as
negative electrodes).
The error bar in HSE is about 0.1, 0.2 and can reach 0.4 V in some
cases, as shown in this paper:
https://www.nature.com/articles/npjcompumats20162.
Best regards
Xavier
On 30/12/2022 17:44, shamik chakrabarti wrote:
> Dear Prof. Xavier,
>
> I have used HSE06 to simulate both C6 (graphene) &
> LiC6 with monoclinic structure & obtained 0.12 V (with respect to Li
> cathode) which matches perfectly with the experimental report.
>
> Looking forward to your further advice Sir.
>
> with regards,
>
>
>
>
>
> On Fri, 30 Dec 2022 at 21:01, xavier rocquefelte
> <xavier.rocquefelte at univ-rennes1.fr> wrote:
>
> One more point the negative electrode is usually graphite and not
> graphene.
>
> To estimate a voltage you need a positive electrode.
>
> Estimating the voltage implies to properly treat not only the
> negative but the positive electrode materials and with the same
> functional.
>
> Best regards
>
> Xavier
>
> On 30/12/2022 16:26, xavier rocquefelte wrote:
>>
>> Dear Shamik
>>
>> I certainly did not follow all the discussion but it seems to me
>> that your objective is reachable if you properly define your
>> parameters.
>>
>> You mention that the band structure is finally not the essential
>> point and you want to have a proper estimation of the voltage.
>>
>> Here are two well-known problems:
>>
>> - Li batteries voltage estimation is usually wrong and
>> corrections must be applied (depending on the functional). I
>> recommend the publications of Ceder's group.
>>
>> - The choice of the functional may be crucial and for carbon GGA
>> is sometimes not the best.
>>
>> I will thus recommend first to choose your functional by
>> estimating properly the band structure of the hexagonal cell of
>> graphene and only after switch to the monoclinic cell to estimate
>> the voltage.
>>
>> Best regards
>>
>> Xavier
>>
>> On 30/12/2022 15:51, shamik chakrabarti wrote:
>>> Dear Prof. Blaha,
>>>
>>> I think the structure as used by me & as can
>>> be used by downloading Graphene CIF file from material project
>>> database are same with different representation. I have checked
>>> the XRD of both the structures in VESTA & they are providing the
>>> same XRD pattern for both the structures. In this regard
>>> lithiation voltage for both the cases should be same. However
>>> the bandstructures need special k points which is available for
>>> hexagonal lattice & not for this monoclinic lattice. However, if
>>> the voltage is accurate I will not bother for the band structure.
>>>
>>> with kind regards,
>>>
>>> On Fri, 30 Dec 2022 at 19:08, shamik chakrabarti
>>> <shamik15041981 at gmail.com> wrote:
>>>
>>> Specially if I want LiC6 unit cell?...
>>>
>>> On Fri, Dec 30, 2022, 18:47 shamik chakrabarti
>>> <shamik15041981 at gmail.com> wrote:
>>>
>>> Dear Prof. Blaha,
>>> . . . . . . Thank you for your reply Sir. I
>>> have a very dumb question. Whether the voltage simulated
>>> by this attached structure will provide the same as will
>>> be provided by the single unit cell?
>>>
>>> With kind regards,
>>>
>>> On Fri, Dec 30, 2022, 18:03 Peter Blaha
>>> <peter.blaha at tuwien.ac.at> wrote:
>>>
>>> This is not the smallest unit cell of graphene but a
>>> 3 times larger
>>> monoclinic cell.
>>>
>>> Start with graphite, remove the atoms at the second
>>> z=0.75 layer and
>>> eventually add some vacuum along z.
>>>
>>>
>>> Am 29.12.2022 um 18:34 schrieb shamik chakrabarti:
>>> > The structure of monolayer Graphenbe as I have
>>> used is attached for your
>>> > reference.
>>> >
>>> > On Thu, 29 Dec 2022 at 18:32, shamik chakrabarti
>>> > <shamik15041981 at gmail.com
>>> <mailto:shamik15041981 at gmail.com>> wrote:
>>> >
>>> > Dear Wien2k users,
>>> >
>>> > I have simulated a
>>> structure of Graphene
>>> > monolayer with primitive cell. I am getting
>>> DOS & voltage
>>> > accurately. However, while plotting band
>>> structure I am facing a
>>> > problem. In hexagonal Graphene the band
>>> structure can be obtained
>>> > with Gamma-M-K-Gamma, where K is the dirac
>>> point. However, in my
>>> > primitive cell I am getting a Brillouin Zone
>>> of reciprocal lattice &
>>> > not able to detect the Dirac point.
>>> >
>>> > The purpose of taking a primitive cell of
>>> monolayer Graphene lies on
>>> > the fact that I need control over all the C atoms.
>>> >
>>> > Looking forward to hearing from you.
>>> >
>>> > --
>>> > Dr. Shamik Chakrabarti
>>> > Research Fellow
>>> > Department of Physics
>>> > Indian Institute of Technology Patna
>>> > Bihta-801103
>>> > Patna
>>> > Bihar, India
>>> >
>>> >
>>> >
>>> > --
>>> > Dr. Shamik Chakrabarti
>>> > Research Fellow
>>> > Department of Physics
>>> > Indian Institute of Technology Patna
>>> > Bihta-801103
>>> > Patna
>>> > Bihar, India
>>> >
>>> > _______________________________________________
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>>> >
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>>> --
>>> --------------------------------------------------------------------------
>>> Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna,
>>> A-1060 Vienna
>>> Phone: +43-1-58801-165300
>>> Email: peter.blaha at tuwien.ac.at WIEN2k:
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>>>
>>> --
>>> Dr. Shamik Chakrabarti
>>> Research Fellow
>>> Department of Physics
>>> Indian Institute of Technology Patna
>>> Bihta-801103
>>> Patna
>>> Bihar, India
>>>
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>> --
>> ------------------------
>> Professeur des Universités de Rennes 1
>> Institut des Sciences Chimiques de Rennes (ISCR)
>> Univ Rennes - CNRS - UMR6226, France
>> https://iscr.univ-rennes1.fr/xavier-rocquefelte
>> ------------------------
>>
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>
> --
> ------------------------
> Professeur des Universités de Rennes 1
> Institut des Sciences Chimiques de Rennes (ISCR)
> Univ Rennes - CNRS - UMR6226, France
> https://iscr.univ-rennes1.fr/xavier-rocquefelte
> ------------------------
>
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>
>
> --
> Dr. Shamik Chakrabarti
> Research Fellow
> Department of Physics
> Indian Institute of Technology Patna
> Bihta-801103
> Patna
> Bihar, India
>
> _______________________________________________
> Wien mailing list
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--
------------------------
Professeur des Universités de Rennes 1
Institut des Sciences Chimiques de Rennes (ISCR)
Univ Rennes - CNRS - UMR6226, France
https://iscr.univ-rennes1.fr/xavier-rocquefelte
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