# Graphene band structure

This example plots the band structure of graphene, a 2D material. 2D band structures are not supported natively (yet), so we manually build a custom path in reciprocal space.

```
using DFTK
using Unitful
using UnitfulAtomic
using LinearAlgebra
using Plots
# Define the convergence parameters (these should be increased in production)
L = 20 # height of the simulation box
kgrid = [6, 6, 1]
Ecut = 15
temperature = 1e-3
# Define the geometry and pseudopotential
a = 4.66 # lattice constant
a1 = a*[1/2,-sqrt(3)/2, 0]
a2 = a*[1/2, sqrt(3)/2, 0]
a3 = L*[0 , 0 , 1]
lattice = [a1 a2 a3]
C1 = [1/3,-1/3,0.0] # in reduced coordinates
C2 = -C1
positions = [C1, C2]
C = ElementPsp(:C; psp=load_psp("hgh/pbe/c-q4"))
atoms = [C, C]
# Run SCF
model = model_PBE(lattice, atoms, positions; temperature)
basis = PlaneWaveBasis(model; Ecut, kgrid)
scfres = self_consistent_field(basis)
# Construct 2D path through Brillouin zone
kpath = irrfbz_path(model; dim=2, space_group_number=13) # graphene space group number
bands = compute_bands(scfres, kpath; kline_density=20)
plot_bandstructure(bands)
```