I am considering the relaxation for the following zigzag graphene nanoribbon.

enter image description here

Here the boundary of the zigzag graphene(C: brown) nanoribbon has been passivated with one H atom. I have performed the spin-polarized and spin-unpolarized calculations with VASP. Surprisingly, I found that the spin-polarized calculation gives me lower total energy. Moreover, the total magnetic momentum can be traced back to the C atom passivated with H atom.

Should the zigzag graphene nanoribbon present a spin-polarized ground state? Although the boundary has been passivated. By the way, I have also passivated the boundary with 2 H atoms and then there is net total residual magnetic momentum. Should I use 2 H atoms to passivate the boundary of the zigzag graphene nanoribbon?


This is consistent with some work we did on graphene nanoribbons a few years ago. We used LDA for this work, though from memory PBE gave similar results. This was using CASTEP, so different pseudopotentials to you and a different implementation of the plane-wave DFT method, so it can be considered independent verification.

Like you, we found that the bare zigzag edge was spin polarised fairly strongly (this is well studied now); passivating with one hydrogen per edge carbon reduced the spin polarisation enormously, but did not completely suppress it; and passivating with two hydrogens per edge carbon led to a non-spin-polarised ground state. The most stable edge structure was the two-hydrogen passivation. We published our findings here:

“Theoretical study of core-loss electron energy-loss spectroscopy at graphene nanoribbon edges”, Nobuyuki Fujita, Philip Hasnip, Matt Probert and Jun Yuan, J. Phys. Condens. Matter 27, 305301 (2015). https://doi.org/10.1088/0953-8984/27/30/305301


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.