Thank you Teng. This is not what I meant. In principle dk could take any value I choose, well beyond 0.0 and 0.5. In particular I'd like my choice to be such that I explicitly include the K point of graphene (notice the uppercase here). Right now I am obtaining eigenvalues at the K point from a bandstructure calculation (ie via interpolation on a rather large k-point mesh). My question is whether or not, in the method developed by Moreno et al, and implemented in siesta, feasible values of dk have been determined for the honeycomb lattice so that the K point is explicitly included. Maybe not. Thank you for your response though, and best regards.
-Salvador. ----- Original Message ----- From: "Teng Yang" <yangt...@imr.ac.cn> To: siesta-l@uam.es Sent: Wednesday, January 6, 2010 12:33:35 AM GMT -05:00 US/Canada Eastern Subject: Re: [SIESTA-L] units of dk in Monkhorst-Pack grid Hi Salvador, dk has two choice, either 0.0 (no shift) or 0.5. Using 0.5 for dk is to shift all your k point by half of the closest k point distance, therefore the most symmetric point (Gamma point) is not inculded, e.g. you choose to calculate using 4 k points in 1st BZ in one dimension, you will split 1st BZ into 4 even parts (from -Pi/a, -Pi/2a, 0, Pi/2a and Pi/a), the k distance is Pi/2a, when you shift dk by 0.5 (by Pi/4a), your new K points are (-3Pi/4, -Pi/4a, Pi/4a, 3Pi/4a). Good luck! --Teng > Dear users, > I am performing a calculation on a graphitic system and would like to include > the K point explicitly into the k-point grid. > Wondering if dk is given in units of pi/a. Your help on this will be greatly > appreciated. > > -- > Salvador Barraza-Lopez > Postdoctoral Fellow > School of Physics > The Georgia Institute of Technology > > Office N205 > 837 State Street Atlanta, Georgia 30332-0430 U.S.A > Tel: (404) 894-0892 Fax: (404) 894-9958 > ======================================== Teng Yang, Ph.D. ------------------ Magnetism and Magnetic Materials Division Shenyang Materials Science National Laboratory Institute of Metal Research Chinese Academy of Sciences 72 Wenhua Road,Shenyang 110016, China +86-24-83978119 (office) +86-15998154791 (mobile) +86-24-23891320 (FAX) work: yangt...@imr.ac.cn personal: yanghait...@msn.com http://www.pa.msu.edu/~yang http://www.msu.edu/~yangteng ======================================== -- Salvador Barraza-Lopez Postdoctoral Fellow School of Physics The Georgia Institute of Technology Office N205 837 State Street Atlanta, Georgia 30332-0430 U.S.A Tel: (404) 894-0892 Fax: (404) 894-9958
