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 -7.916428216966 -0.69 5.1 109ms
2 -7.921204833581 -2.32 -1.52 1.0 53.6ms
3 -7.921404426437 -3.70 -2.49 1.4 56.7ms
4 -7.921440913583 -4.44 -2.82 2.8 76.0ms
5 -7.921441575019 -6.18 -2.97 1.1 66.6ms
6 -7.921442007863 -6.36 -4.51 1.0 54.3ms
7 -7.921442021779 -7.86 -4.58 2.9 83.2ms
8 -7.921442022127 -9.46 -5.21 1.0 54.4ms
9 -7.921442022142 -10.84 -5.69 1.4 58.4ms
10 -7.921442022144 -11.74 -5.92 1.1 55.6ms
11 -7.921442022144 -12.42 -6.55 1.1 56.4ms
12 -7.921442022144 -13.26 -7.39 1.8 76.3ms
13 -7.921442022144 -14.75 -7.47 2.1 70.6ms
14 -7.921442022144 + -Inf -8.15 1.0 55.7msNext 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 2.05s Non-interacting
1 0 1 0.31 52.7 3.91s
2 0 2 -0.52 47.2 1.30s
3 0 3 -2.40 41.8 1.19s
4 0 4 -4.46 30.0 2.36s
5 0 5 -6.46 17.6 776ms
6 0 6 -8.92 4.0 420ms
7 1 1 -7.86 55.7 1.79s Restart
8 1 2 -8.97 5.5 451ms
72.9 1.71s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.58s Non-interacting
1 0 1 0.31 52.7 1.54s
2 0 2 -0.52 47.2 1.31s
3 0 3 -2.40 41.8 1.21s
4 0 4 -4.46 30.0 954ms
5 0 5 -6.46 17.6 710ms
6 0 6 -8.92 4.0 404ms
7 1 1 -7.86 55.7 1.91s Restart
8 1 2 -8.97 5.5 452ms
72.9 1.82s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.68s Non-interacting
1 0 1 0.31 52.7 1.59s
2 0 2 -0.52 47.2 1.36s
3 0 3 -2.40 41.8 1.24s
4 0 4 -4.46 30.0 991ms
5 0 5 -6.46 17.6 707ms
6 0 6 -8.92 4.0 420ms
7 1 1 -7.86 55.7 1.89s Restart
8 1 2 -8.97 5.5 445ms
72.9 1.81s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.64s Non-interacting
1 0 1 0.31 52.7 1.58s
2 0 2 -0.52 47.2 1.34s
3 0 3 -2.40 41.8 1.22s
4 0 4 -4.46 30.0 976ms
5 0 5 -6.46 17.5 716ms
6 0 6 -8.92 4.0 422ms
7 1 1 -7.85 55.7 1.87s Restart
8 1 2 -9.02 5.5 450ms
72.9 1.80s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.62s Non-interacting
1 0 1 0.31 52.7 1.56s
2 0 2 -0.52 47.2 2.85s
3 0 3 -2.40 41.8 1.19s
4 0 4 -4.46 30.0 929ms
5 0 5 -6.46 17.5 675ms
6 0 6 -8.92 4.0 414ms
7 1 1 -7.85 55.7 1.83s Restart
8 1 2 -9.02 5.5 444ms
72.9 1.74s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.59s Non-interacting
1 0 1 0.31 52.7 1.53s
2 0 2 -0.52 47.2 1.32s
3 0 3 -2.40 41.8 1.21s
4 0 4 -4.46 30.0 963ms
5 0 5 -6.46 17.5 692ms
6 0 6 -8.92 4.0 415ms
7 1 1 -7.85 55.7 1.84s Restart
8 1 2 -9.02 5.5 442ms
72.9 1.80s Final orbitals
88.812998 seconds (101.47 M allocations: 80.490 GiB, 9.70% gc time, 8.86% compilation time: 100% of which was recompilation)These are the final phonon frequencies:
phret_q0.frequencies6-element Vector{Float64}:
-0.0034981553636715262
-0.002977451164211976
-0.002977451163924873
0.004302230616714109
0.0043022306167319405
0.004353201747521175