[Wien] confusion regarding band structure of Graphene
shamik chakrabarti
shamik15041981 at gmail.com
Fri Dec 30 18:47:29 CET 2022
Dear Prof. Xavier,
Thanks a lot for your reference Sir. It will illuminate
further understanding in myself.
Happy New Year! :)
On Fri, 30 Dec 2022 at 22:57, xavier rocquefelte <
xavier.rocquefelte at univ-rennes1.fr> wrote:
> 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
>>>>> >
>>>>> > _______________________________________________
>>>>> > Wien mailing list
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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: http://www.wien2k.at
>>>>> WWW: http://www.imc.tuwien.ac.at
>>>>>
>>>>> -------------------------------------------------------------------------
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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, Francehttps://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, Francehttps://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 listWien at zeus.theochem.tuwien.ac.athttp://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
> SEARCH the MAILING-LIST at: http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html
>
> --
> ------------------------
> Professeur des Universités de Rennes 1
> Institut des Sciences Chimiques de Rennes (ISCR)
> Univ Rennes - CNRS - UMR6226, Francehttps://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
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