[Pw_forum] regarding supercells in graphene nanoribbons

Wed Jun 17 13:23:15 CEST 2015

Dear sir

Firstly i am taking Zigzag nanoribbons,and width of the ribbon is 4 ,while
nearest neighbor hopping parameter is equal to 1,while hoppings inside the
leads is t,while hoppings between the lead and the sample is t
itself.,/number of energy points are 200 and upper limit of the energy
interval =3.5,while lower energy interval is -3.5.Now my Hamiltonian is
becoming 24 *24 order in terms of blocks matrices.this is the geometry of
the Graphene nano ribbon sir

regards

Surender Pratap
Research Scholar
Physics Department
BITS Pilani,Pilani Campus Rajsthan-333031(INDIA)...
Mob-7891949445

*Birla Institute of Technology & Science,* Pilani

Pilani 333031, Rajasthan, India

On Wed, Jun 17, 2015 at 2:24 PM, Giovanni Cantele <
giovanni.cantele at spin.cnr.it> wrote:

> Dear S.P.,
>
> unfortunately providing help will be impossible if you do not try to
> CLEARLY explain what you want to do.
>
> i) You did not say which orientation of the nanoribbon you are
> considering, maybe armchair ?
> ii) you said that you first considered a width equivalent to 4 atomic
> lines, then 8, then you said you are not able to understand, but you did
> not say WHAT you are not able to understand.
> iii) I would never write any code calculating conductance and any property
> before getting a clear understanding of the system I want to investigate.
> Try to start from simple things, that might help you to understand for
> example if you are using the correct supercell and atomic positions.
>
> Giovanni
>
> On 17 Jun 2015, at 06:02, Surender Pratap <suren1986dhalaria at gmail.com>
> wrote:
>
> Thanks sir,but i have written it in matlab code,and i am getting the LDOS
> ,conductance as well as EK diagram,there is hoppings inside supercells also
> sir,I can share the matlab script here if you want.
>
> regards
>
>
> Surender Pratap
> Research Scholar
> Physics Department
> BITS Pilani,Pilani Campus Rajsthan-333031(INDIA)...
> Mob-7891949445
>
> <color_strip_BITS.jpg>
>
> *Birla Institute of Technology & Science,* Pilani
>
> Pilani 333031, Rajasthan, India
>
> On Wed, Jun 17, 2015 at 8:58 AM, Sanjeev Gupta <physics.skgupta at gmail.com>
> wrote:
>
>> Hi, SP
>>
>> perhaps positions of atom is not correct and they repeat in second
>> layers, but again with Giovanni reply, share your input so user look and
>> comment correctly.
>>
>> SKG
>>
>> On Tue, Jun 16, 2015 at 8:16 PM, Surender Pratap <
>> suren1986dhalaria at gmail.com> wrote:
>>
>>> Thanks a lot sir,i have taken width of the ribbon is 4,but now in my
>>> calculation it is becoming two times ,that means 8 sir,which i am not able
>>> to understand sir,why it is happening like this sir.Please help me in this
>>> matter sir.
>>> regards
>>>
>>> Surender Pratap
>>> Research Scholar
>>> Physics Department
>>> BITS Pilani,Pilani Campus Rajsthan-333031(INDIA)...
>>> Mob-7891949445
>>>
>>> <color_strip_BITS.jpg>
>>>
>>> *Birla Institute of Technology & Science,* Pilani
>>>
>>> Pilani 333031, Rajasthan, India
>>>
>>> On Wed, Jun 17, 2015 at 1:59 AM, Giovanni Cantele <
>>> giovanni.cantele at spin.cnr.it> wrote:
>>>
>>>> Dear S. P.,
>>>>
>>>> 8 could be the right or the wrong Number, it depends on which are the
>>>> orientation and the width of the nanoribbon. How did you choose that
>>>> number? Nobody will be able to provide help if you do not provide
>>>> sufficient information.
>>>>
>>>> Giovanni
>>>>
>>>> Inviato da iPad
>>>>
>>>> Il giorno 16/giu/2015, alle ore 14:45, Surender Pratap <
>>>> suren1986dhalaria at gmail.com> ha scritto:
>>>>
>>>> Dear all users
>>>>
>>>> Can any body tell me please how many atoms are taken into supercells of
>>>> Hamiltonian,in my calculation of graphene nanoribbons ,i am taking 8,is it
>>>> right to take 8 ,how 8 are coming i am not able to understand.
>>>>
>>>> regards
>>>>
>>>> Surender Pratap
>>>> Research Scholar
>>>> Physics Department
>>>> BITS Pilani,Pilani Campus Rajsthan-333031(INDIA)...
>>>> Mob-7891949445
>>>>
>>>> <color_strip_BITS.jpg>
>>>>
>>>> *Birla Institute of Technology & Science,* Pilani
>>>>
>>>> Pilani 333031, Rajasthan, India
>>>>
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>>>
>>>
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>>
>>
>>
>> --
>> With Best Regards,
>>
>> ------------------------------------
>> Dr. Sanjeev Kumar Gupta
>> Fulbright Post-Doctoral Scholar
>> Dept. of Physics
>> Michigan Technological University
>> 1400 Townsend Drive, Houghton
>> MI 49931, USA
>> ------------------------------------
>>
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>
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>
> --
>
> Giovanni Cantele, PhD
> CNR-SPIN
> c/o Dipartimento di Fisica
> Universita' di Napoli "Federico II"
> Complesso Universitario M. S. Angelo - Ed. 6
> Via Cintia, I-80126, Napoli, Italy
> e-mail: giovanni.cantele at spin.cnr.it
> Phone: +39 081 676910
> Skype contact: giocan74
>
> ResearcherID: http://www.researcherid.com/rid/A-1951-2009
> Web page: http://people.na.infn.it/~cantele
>
>
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