Dear Steven and MPB's users,
I would like to calculate the defect modes existing in a triangular PC
*slab whith a line defect of W0.90*. I have formed a geometry by moving up
and down the air holes around the linear defect but the band structure
obtained is wrong: defect modes appear outside the expected band gap
region.Could you please help me finding the way to obtain the correct
structure?
(define-param h 0.5) ; the thickness of the slab
(define-param a1 0.5) ; lattice vector x triangular distribution
(define-param a2 0.867) ; lattice vector y triangular distribution
(define-param wd 0.7803) ; ;es el valor de h
(define-param eps 11.97) ; the dielectric constant of the slab
(define-param loweps 1.0) ; the dielectric constant of the substrate
(define-param r 0.275) ; the radius of the holes
(define-param supercell-h 4) ; height of the supercell
(set! default-material (make dielectric (epsilon 11.97)))
(define-param supercell-y (+ 12 (* 2 wd))) ; the (odd) number of lateral
supercell periods
(set! geometry-lattice (make lattice
(basis1 1 0)
(basis2 0 (/ (sqrt 3) 2))
(size 1 supercell-y supercell-h)))
(set! geometry
(list (make block (material (make dielectric (epsilon loweps)))
(center 0 0 (* 0.25 supercell-h))
(size infinity infinity (* 0.5 supercell-h)))
(make block (material (make dielectric (epsilon eps)))
(center 0) (size infinity infinity h))
))
(set! geometry
(append geometry (list
(make cylinder (material air)
(center 0.5 wd 0) (radius r) (height supercell-h))
(make cylinder (material air)
(center 0.5 (- 0 wd) 0) (radius r) (height supercell-h))
(make cylinder (material air)
(center 0 (+ wd a2) 0) (radius r) (height supercell-h))
(make cylinder (material air)
(center 0 (- 0 (+ wd a2)) 0) (radius r) (height supercell-h))
(make cylinder (material air)
(center 0.5 (+ wd (* 2 a2)) 0) (radius r) (height supercell-h))
(make cylinder (material air)
(center 0.5 (- 0 (+ wd (* 2 a2))) 0) (radius r) (height
supercell-h))
(make cylinder (material air)
(center 0 (- 0 (+ wd (* 3 a2))) 0) (radius r) (height
supercell-h))
(make cylinder (material air)
(center 0 (+ wd (* 3 a2)) 0) (radius r) (height supercell-h))
(make cylinder (material air)
(center 0.5 (- 0 (+ wd (* 4 a2))) 0) (radius r) (height
supercell-h))
(make cylinder (material air)
(center 0.5 (+ wd (* 4 a2)) 0) (radius r) (height supercell-h))
(make cylinder (material air)
(center 0 (- 0 (+ wd (* 5 a2))) 0) (radius r) (height
supercell-h))
(make cylinder (material air)
(center 0 (+ wd (* 5 a2)) 0) (radius r) (height supercell-h))
)))
(define Gamma (vector3 0 0 0))
(define K' (lattice->reciprocal (vector3 0.5 0 0))) ; edge of Brillouin
zone.
(set! k-points (interpolate 4 (list Gamma K')))
(define-param extra-bands 5) ; number of extra bands to compute above the
gap
(set-param! num-bands 10)
(define-param res 32) ; the resolution (grid points/a)
(set! grid-size (vector3 res (* res supercell-y) 1))
(run-zeven (output-at-kpoint K' fix-hfield-phase output-hfield-z))
(display-eigensolver-stats)
I thank you very much, and looking forward to your reply.
Regards, Imanol Andonegui
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