کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1811318 1025592 2011 6 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Unit cell dependence of optical matrix elements in tight-binding theory: The case of zigzag graphene nanoribbons
موضوعات مرتبط
مهندسی و علوم پایه فیزیک و نجوم فیزیک ماده چگال
پیش نمایش صفحه اول مقاله
Unit cell dependence of optical matrix elements in tight-binding theory: The case of zigzag graphene nanoribbons
چکیده انگلیسی

In the tight-binding theory, momentum matrix elements (MMEs) needed to calculate the optical properties are normally computed using a formulation based on the gradient of the Hamiltonian in the kk space. We demonstrate the inadequacy of this formulation by considering the case of zigzag graphene nanoribbons. We show that one obtains wrong values of MMEs, in violation of the well-known selection rules, if the unit cell chosen in the calculations does not incorporate the symmetries of the bulk. This is in spite of the fact that the band structure is insensitive to the choice of the unit cell. We substantiate our results based on group-theoretic arguments. Our observations will open an avenue for proper formulation of MMEs.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Physica B: Condensed Matter - Volume 406, Issue 19, 1 October 2011, Pages 3538–3543
نویسندگان
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