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Dear Zeina,
<div>one possibility is to simulate the "merging" region only, together with enough graphene on one side and CNT on the other so that the hopping energies and onsite energies far away from the interface are the same of the pristine graphene and CNT only.</div>
<div>You can then use the correct hopping and onsite energies for each region (those in the intermediate region from this last simulation, and the hoppings far away from the two pristine simulations). This can be done with Wannier90 or with other codes that
calculate the transmission given the proper Tight-Binding Hamiltonian.</div>
<div>In practice, things can get more complicated, e.g. if there is charge accumulation that can shift the relative hopping energies of the two materials, but this depends on the specific material.</div>
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<div>Otherwise, if the global system is not too big, you can try to simulate directly the whole system. Just remember that the code still assumes periodic boundary conditions in the 1D direction, so you will probably need to create, e.g., a system with two
junctions (from CNT to graphene and then back to CNT); however in this case, you will measure the conductance through both junctions, that may or may not be what you want.</div>
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<div>Best,</div>
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<div>Giovanni</div>
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<div>-- </div>
<div>Giovanni Pizzi<br>
Post-doctoral Research Scientist<br>
EPFL STI IMX THEOS<br>
MXC 340 (Bātiment MXC)<br>
Station 12<br>
CH-1015 Lausanne (Switzerland)<br>
Phone: +41 21 69 31124<br>
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<div>On 13 Nov 2014, at 22:04, Zeina Al-Dolami wrote:</div>
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<div dir="ltr">Dr. Arash and Dr.Giovanni,
<div>Thanks so much for your help. It worked and I got what I needed :) I have one more question that I am not sure about its answer. My question is that what should I do to include or merge two systems together? To explain, let's assume that I would need
to find the quantum conductance for a system that has a carbon nano tube and a sheet of graphene. Also, let's assume that I have already calculated the quantum conductance when they are separated, i.e. each one is a system by itself. Now, I need to find the
quantum conductance for the whole system that has both in a device. Would it be just identifying the positions and k points for that whole new system or there is something else that I need to consider to investigate the difference between bringing them together
in one system and separated? Any answer or hint is greatly appreciated. Many thanks in advance</div>
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<div>Zeina </div>
<div>PhD candidate in MEPH</div>
<div>University of Arkansas</div>
<div>Fayetteville, AR 72703 </div>
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