Phonon computations
This is a quick sketch how to run a simple phonon calculation using DFTK.
Practical phonon computations have only seen rudimentary testing as of now. As of now we do not yet recommend relying on this feature for production calculations. We appreciate any issues, bug reports or PRs.
First we run an SCF calculation.
using AtomsBuilder
using DFTK
using PseudoPotentialData
pseudopotentials = PseudoFamily("cp2k.nc.sr.lda.v0_1.semicore.gth")
model = model_DFT(bulk(:Si); pseudopotentials, functionals=LDA())
basis = PlaneWaveBasis(model; Ecut=10, kgrid=[4, 4, 4])
scfres = self_consistent_field(basis, tol=1e-8);n Energy log10(ΔE) log10(Δρ) Diag Δtime
--- --------------- --------- --------- ---- ------
1 -7.916423615035 -0.69 4.6 108ms
2 -7.921198502742 -2.32 -1.52 1.0 54.7ms
3 -7.921401314302 -3.69 -2.49 1.4 69.9ms
4 -7.921440984326 -4.40 -2.80 2.8 78.9ms
5 -7.921441449936 -6.33 -2.89 1.0 54.8ms
6 -7.921442008366 -6.25 -4.51 1.0 55.3ms
7 -7.921442021593 -7.88 -4.47 3.2 89.3ms
8 -7.921442022118 -9.28 -5.13 1.0 54.8ms
9 -7.921442022130 -10.94 -5.16 1.1 56.6ms
10 -7.921442022143 -10.89 -5.87 1.0 67.7ms
11 -7.921442022144 -12.04 -5.69 1.8 64.0ms
12 -7.921442022144 -12.74 -5.76 1.0 57.3ms
13 -7.921442022144 -12.93 -5.87 1.0 108ms
14 -7.921442022144 -13.18 -6.11 1.0 56.2ms
15 -7.921442022144 -13.53 -7.65 1.0 57.0ms
16 -7.921442022144 + -15.05 -6.61 2.2 74.3ms
17 -7.921442022144 -14.57 -7.30 2.0 94.4ms
18 -7.921442022144 + -Inf -7.87 1.0 56.4ms
19 -7.921442022144 -15.05 -8.13 1.0 57.1msNext we compute the phonon modes at the q-point [1/4, 1/4, 1/4].
scfres = DFTK.unfold_bz(scfres)
phret_q0 = @time DFTK.phonon_modes(scfres; q=[0.25, 0.25, 0.25]);Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.99s Non-interacting
1 0 1 0.31 52.7 3.71s
2 0 2 -0.52 47.2 1.32s
3 0 3 -2.40 41.8 1.21s
4 0 4 -4.46 29.9 997ms
5 0 5 -6.46 17.5 709ms
6 0 6 -8.92 4.0 419ms
7 1 1 -7.85 55.9 3.28s Restart
8 1 2 -8.95 5.5 414ms
72.9 1.83s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.56s Non-interacting
1 0 1 0.31 52.7 1.56s
2 0 2 -0.52 47.2 1.33s
3 0 3 -2.40 41.8 1.21s
4 0 4 -4.46 29.9 972ms
5 0 5 -6.46 17.5 719ms
6 0 6 -8.92 4.0 425ms
7 1 1 -7.85 55.9 1.84s Restart
8 1 2 -8.95 5.5 467ms
72.8 1.74s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.60s Non-interacting
1 0 1 0.31 52.7 1.55s
2 0 2 -0.52 47.2 1.33s
3 0 3 -2.40 41.8 1.21s
4 0 4 -4.46 29.9 973ms
5 0 5 -6.46 17.5 697ms
6 0 6 -8.92 4.0 435ms
7 1 1 -7.85 55.9 1.85s Restart
8 1 2 -8.95 5.5 450ms
72.9 1.74s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.1 1.62s Non-interacting
1 0 1 0.31 52.7 1.54s
2 0 2 -0.52 47.2 1.33s
3 0 3 -2.40 41.8 1.20s
4 0 4 -4.46 29.9 962ms
5 0 5 -6.46 17.5 710ms
6 0 6 -8.92 4.0 425ms
7 1 1 -7.84 55.9 1.85s Restart
8 1 2 -9.02 5.6 472ms
72.9 1.73s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.57s Non-interacting
1 0 1 0.31 52.7 1.52s
2 0 2 -0.52 47.2 1.32s
3 0 3 -2.40 41.8 1.21s
4 0 4 -4.46 29.9 953ms
5 0 5 -6.46 17.5 815ms
6 0 6 -8.92 4.0 1.65s
7 1 1 -7.84 55.9 1.71s Restart
8 1 2 -9.02 5.6 432ms
72.9 1.71s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.57s Non-interacting
1 0 1 0.31 52.7 1.54s
2 0 2 -0.52 47.2 1.32s
3 0 3 -2.40 41.8 1.20s
4 0 4 -4.46 29.9 966ms
5 0 5 -6.46 17.5 702ms
6 0 6 -8.92 4.0 433ms
7 1 1 -7.84 55.9 1.86s Restart
8 1 2 -9.02 5.6 459ms
72.9 1.74s Final orbitals
86.484021 seconds (101.36 M allocations: 80.461 GiB, 8.29% gc time, 7.61% compilation time: 100% of which was recompilation)These are the final phonon frequencies:
phret_q0.frequencies6-element Vector{Float64}:
-0.003498155351826228
-0.002977451153455158
-0.002977451153453954
0.004302230640574454
0.004302230640584765
0.004353201770292334