[Wien] hcp.klist

[Jeff Spirko]

On Mon, Aug 11, 2003 at 04:18:50PM -0700, Shen Li Qiu wrote:
> Dear All,
>  The hcp.klist in SRC_templates gives the klist from Sigma to M to K as
> follows.

> SIGMA        10    0    0   40  2.0
...
> M            20    0    0   40  2.0
>              29    2    0   60  2.0
...
> K            20   20    0   60  2.0

> Why should kx jumps from 20 to 29 then decreases when it goes from M to K?

Because the divisor in the fifth column changes to 60.

> It seems to me that kx should be constant (=20) from M to K.

The K point is indeed (1/3 b1 + 1/3 b2).  The confusion is because
the unit vectors b1 and b2 are not perpendicular, so contributions
by b2 are compensated by decreases in the b1 component so (K dot b1)
remains constant as desired.

-- 
Jeff Spirko   spirko at lehigh.edu   spirko at yahoo.com   WD3V   |=>

The study of non-linear physics is like the study of non-elephant biology.

All theoretical chemistry is really physics;
and all theoretical chemists know it. -- Richard P. Feynman