On Tuesday 30 May 2006 11:39, Cyrille Barreteau wrote: > I am generating the k points by the following input: > > K_POINTS automatic > n1 n2 1 0 0 0 > > According to the manual the code is using MP k points but I am a bit > surprised to find that the Gamma= 0,0,0 point is always present in > the k points list whatever the parity of the integers n1 and n2.
K_POINTS automatic n1 n2 n3 j1 j2 j3 yields a grid of k-points: k(i1,i2,i3) = (i1+j1/2) * g1/n1 + (i2+j2/2) * g2/n2 + (i3+j3/2) * g3/n3 where g1, g2, g3 are the vectors that generate the reciprocal lattice; the indices i1, i2, i3, run from 0 to n1-1, n2-1, n3-1 respectively; j1, j2, j3 can be either 0 (no offset, k=0 in the grid) or 1 (with offset, k=0 not in the grid). What is usually referred to as "Monkhorst-Pack" grid has offset and does not contain k=0 . Of course, only inequivalent k-points are actually used Paolo -- Paolo Giannozzi e-mail: giannozz at nest.sns.it Scuola Normale Superiore Phone: +39/050-509876, Fax:-563513 Piazza dei Cavalieri 7 I-56126 Pisa, Italy
