Hi everybody,
I have a question about one particular script. The one below is written for
3D opal structure of silica spheres with dielectric constant ~1.90. When
this band structure is completed the pseudo PBG opens at the L point of the
BZ for the FCC structure. However, literature shows this gap should be at
a/lambda = ~0.65. In the script below it is at ~0.75. I am not sure how this
could be fixed. I do this as an experiment to see if I can have confidence
that future ctl files written will give the correct output.
If anyone could see where the problem is could you please help me.
Regards,
Vedran
(set! geometry-lattice (make lattice
(basis-size (sqrt 0.5) (sqrt 0.5) (sqrt 0.5))
(basis1 0 1 1)
(basis2 1 0 1)
(basis3 1 1 0)))
; These are the lengths of basis 1, basis2 and basis3 vectors, respectively.
(set! k-points (interpolate 9 (list
(vector3 0 0.5 0.5) ;define X
(vector3 0.25 0.625 0.625) ;define U
(vector3 0.5 0.5 0.5) ;define L
(vector3 0 0 0) ;define Gamma
(vector3 0 0.5 0.5) ;define X
(vector3 0.25 0.5 0.75) ;define W
(vector3 0.375 0.375 0.75)))) ;define K
; Now define the geometry...
(define-param r 0.275) ; The radius of the silica sphere
(define-param eps 1.90) ; the dielectric constant for this material
(define diel (make dielectric (epsilon eps)))
(set! geometry (list
(make sphere (center 0 0 0) (radius r)
(material diel))))
(set! resolution 32)
(set! num-bands 10)
(run)
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