add pythtb band visualization example

.github/workflows/documentation.yml

@@ -29,7 +29,7 @@ jobs:
       - name: Install documentation dependencies
         run: sudo apt-get update && sudo apt-get install -y xorg-dev mesa-utils xvfb libgl1 freeglut3-dev libxrandr-dev libxinerama-dev libxcursor-dev libxi-dev libxext-dev libcairo2-dev libfreetype6-dev libffi-dev libjpeg-dev libpng-dev libz-dev
       - name: Install dependencies
-        run: DISPLAY=:0 xvfb-run -s '-screen 0 1024x768x24' julia --project=docs/ -e 'using Pkg; Pkg.develop(PackageSpec(path=pwd())); Pkg.instantiate()'
+        run: DISPLAY=:0 xvfb-run -s '-screen 0 1024x768x24' julia --project=docs/ -e 'ENV["PYTHON"]=""; using Pkg; Pkg.develop(PackageSpec(path=pwd())); Pkg.instantiate(); using Conda; Conda.pip_interop(true); Conda.pip("install", "pythtb")'
       - name: Build and deploy
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }} # If authenticating with GitHub Actions token

docs/Project.toml

@@ -1,5 +1,6 @@
 [deps]
 Brillouin = "23470ee3-d0df-4052-8b1a-8cbd6363e7f0"
+Conda = "8f4d0f93-b110-5947-807f-2305c1781a2d"
 Documenter = "e30172f5-a6a5-5a46-863b-614d45cd2de4"
 DocumenterInterLinks = "d12716ef-a0f6-4df4-a9f1-a5a34e75c656"
 GLMakie = "e9467ef8-e4e7-5192-8a1a-b1aee30e663a"

docs/src/pages/viz/band.md

@@ -7,9 +7,50 @@ visualize k-paths.
 
 ## Energy bands
 
-!!! note "In progress"
-    This will be added soon
+In the following example, we plot the band structure of graphene defined as a tight binding model in PythTB.
+This serves to reproduce the [PythTB homepage example](https://www.physics.rutgers.edu/pythtb/) using AutoBZ.jl and highlight the [`load_pythtb_data`](@ref) interface.
+
+```@example
+using PyCall
+py"""
+from pythtb import *
+
+# lattice vectors and orbital positions
+lat=[[1.0, 0.0], [0.5, np.sqrt(3.0)/2.0]]
+orb=[[1./3., 1./3.], [2./3., 2./3.]]
+
+# two-dimensional tight-binding model
+gra=tb_model(2, 2, lat, orb)
+
+# define hopping between orbitals
+gra.set_hop(-1.0, 0, 1, [ 0, 0])
+gra.set_hop(-1.0, 1, 0, [ 1, 0])
+gra.set_hop(-1.0, 1, 0, [ 0, 1])
+
+k=[[0.0, 0.0],[1./3., 2./3.],[0.5,0.5]]
+path=gra.k_path(k, 100)
+"""
+gra = py"gra"
+(k_vec,k_dist,k_node)=py"path"
+
+using AutoBZ
+h,bz = load_pythtb_data(gra)
+
+using LinearAlgebra
+hk = getproperty.(eigen.(h.(eachrow(k_vec))), :values)
+
+using GLMakie
+fig = Figure()
+ax = Axis(fig[1,1]; xticks = (k_node, ["Γ", "K", "M"]))
+series!(ax, k_dist, stack(hk))
+save("grapheneband.png", fig); nothing # hide
+```
+
+![Graphene band kpath](grapheneband.png)
 
 ## Band velocities
 
-To overlay band velocities on the k-ath 
+!!! note "In progress"
+    This will be added soon
+
+To overlay band velocities on the k-path