how to analyse the distribution of MPSH state?

[demo77]

Dear Sir:
  We have investigated the electronic transport properties of heteronanotubes by joining a zigzag (6,0) CNT and a zigzag (6,0) BNNT with different atomic compositions and joint configurations. The heteronanotubes are sandwiched between two 4×4 Au (111) electrodes. We considered four models: In junction A, CNT and BNNT are joined by C-N bonds; In junction B, CNT and BNNT are joined by C-B bonds. We caculated their MPSH (please see the figure attached).
  We found that, for the LUMO in junction B, there is large density on the interface between CNT and BNNT. However, for the LUMO in junction A, there is no any density on the interface between CNT and BNNT.
  Why the difference? What is the reason for the difference? And could you do a favor to tell us how to analyse the distribution of MPSH state?

Thank you in advance for your!

Best regards,
Yours sincerely,

Peng Zhao

[Anders Blom]

I suggest you do another calculation where you join a C-C and a B-N tube in a periodic setting, using the two types of interfaces you have, and see if the effect can be reproduced. If so, it's simply a chemical effect of how C binds to B or N in this geometry. That is, take out the central region and calculate it with many k-points in C, and do a similar projection.

Make sure in all cases to project on enough atoms to support your conclusion (the preferred projection is the entire central region).