[Wien] confusion regarding band structure of Graphene
xavier rocquefelte
xavier.rocquefelte at univ-rennes1.fr
Fri Dec 30 16:26:26 CET 2022
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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> --
> --------------------------------------------------------------------------
> 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
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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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