Dear MPB User Community, I am attempting to produce the band diagram for the single network gyroid shown in Figure 2a of "Weyl points and line nodes in gyroid photonic crystals", by Ling Lu*, Liang Fu, John D. Joannopoulos and Marin Soljacˇic´, Nature Photonics 2013.42. Although MPB (via my ctl file) accurately produces the band gap and many features of the archived diagram, the first and second bands strangely go almost to zero at k-points H': 2pi (0,0,1)/a and H: 2pi(0,1,0). Also, a plot of the epsilon field looks good.
This feature does not appear in Lu's plot. I do not understand what has gone wrong. If someone could help me fix the problem with my simulation, I would be very grateful. My ctl file is shown below. Thank you. Doug Nance ; BCC lattice for gyroid ; t = 0 <=> phi = 0.5 ; t = -1 <=> phi = 0.17 ; t = -0.3 <=> phi = 0.40 ; (define pi 3.141592654) (define a 1.0) (define num 2.0) (define numpioa (/ (* num pi) a)) (define fr 0.0) (define t 1.1) (define epsc 16.0) (define epsa 1.0) (define sx 0.0) (define cx 0.0) (define sy 0.0) (define cy 0.0) (define sz 0.0) (define cz 0.0) (define (px p) (vector3-x (lattice->cartesian p))) (define (py p) (vector3-y (lattice->cartesian p))) (define (pz p) (vector3-z (lattice->cartesian p))) (define (eps-func p) (set! sx (sin (* numpioa (px p)))) (set! cx (cos (* numpioa (px p)))) (set! sy (sin (* numpioa (py p)))) (set! cy (cos (* numpioa (py p)))) (set! sz (sin (* numpioa (pz p)))) (set! cz (cos (* numpioa (pz p)))) (set! fr (+ (* sx cy) (+ (* sy cz) (* cx sz)))) (make dielectric (epsilon (if (> fr t) epsc epsa )))) (set! geometry-lattice (make lattice (basis-size (sqrt 0.75) (sqrt 0.75) (sqrt 0.75)) (basis1 -1 1 1) (basis2 1 -1 1) (basis3 1 1 -1))) (set! k-points (interpolate 4 (list (vector3 0 0 1) ; H' (vector3 0 0 0) ; Gamma (vector3 -0.5 0.5 0.5) ; P (vector3 0 0 1) ; H' (vector3 0 0.5 0.5) ; N (vector3 0 0 0) ; Gamma (vector3 0 1 0) ; H (vector3 -0.5 0.5 0.5) ; P (vector3 0 0.5 0.5)))) ; N (set! default-material (make material-function (material-func eps-func))) (set-param! resolution 32) (set-param! mesh-size 3) (set-param! num-bands 6) (run) _______________________________________________ mpb-discuss mailing list mpb-discuss@ab-initio.mit.edu http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/mpb-discuss