[Wien] confusion regarding band structure of Graphene
shamik chakrabarti
shamik15041981 at gmail.com
Fri Dec 30 17:44:52 CET 2022
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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>>>> > SEARCH the MAILING-LIST at:
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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
>
> _______________________________________________
> Wien mailing listWien at zeus.theochem.tuwien.ac.athttp://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
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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
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