I think that the energy band in lead should be the semimetallic band of zigzag-edge graphene nanoribbon regardless of the parameter r.
Did you plot the system and the dispersion of the lead? I suspect one of the edges has dangling bonds (corresponding to the "bearded" boundary condition). This would open a gap in the lead band structure.
If the band in lead is incorrect and changes from metall to insulator depending on the parameter r, how can i trust the resulting conductance of scattering region ? So, I thought someting is wrong.
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보낸사람: Anton Akhmerov email@example.com 받는사람 : 고운 firstname.lastname@example.org 참조 : "email@example.com" firstname.lastname@example.org 날짜: 2016년 2월 28일 일요일, 00시 20분 50초 +0900 제목: Re: [Kwant] Problems with band in tutoral 2.5 graphene
What exactly do you want to fix? From your description I didn't notice anything going wrong.
On Sat, Feb 27, 2016 at 6:25 AM, 고운 email@example.com wrote:
Hello, I am just starting with KWANT. I have a question about the energy band in lead. In the tutorial "2.5 Beyond square lattices: graphene", the energy band in lead is semimetallic and is consistent with that of zigzag-edge graphene nanoribbon when "r=10" ( default value given in the tutorial). However, when I set r=9 (or a value larger than 10), the energy band in lead becomes insulating and the conductance of scattering region also changes greatly. How can I fix it?