Messages

1

General Questions and Answers / Re: Negative differential conductance in perfect zigzag GNR?

« on: July 3, 2013, 05:51 »

I have performed the self-consistent calculation for zigzag nanoribbons with N odd and the result indeed shows linear current voltage response with much higher conductance which agrees with literature.

Thanks

2

General Questions and Answers / Re: Negative differential conductance in perfect zigzag GNR?

« on: July 2, 2013, 16:27 »

So, there is no problem with device set up or calculation. Then the result shows an interesting phenomenon for this type of structure.

Thank you for your helpful explanation.

3

General Questions and Answers / Re: Negative differential conductance in perfect zigzag GNR?

« on: July 1, 2013, 19:15 »

Hi nori,

Thank you for your reply.

The result is unexpected for me because it contradicts with literature, e.g PRL 100, 206802 (2008). The I-V characteristics of perfect zigzag graphene ribbons should exhibit linear response. Here, the negative differential conductance appears even for small bias which is quite strange.

4

General Questions and Answers / Negative differential conductance in perfect zigzag GNR?

« on: July 1, 2013, 04:48 »

Hi all,

I have set up a simple device structure consisting of 8 zigzag GNRs (see attached image). I used the extended Huckel method with Cerda parameter set for Carbon and Hydrogen, performed the calculation self-consistently with energies = (-2,2,101), kpoints = (1,1,100). The calculation for bias from 0V to 0.6V in step 0.1V followed the tutorial http://quantumwise.com/publications/tutorials/mini-tutorials/98-i-v-curve-and-voltage-drop (see attached scripts).

The results show negative differential conductance in the I-V curve which is quite unexpected. Could you please let me know if there is anything miscalculated or any problem with the device set up?

Thank you very much