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 -7.916443363740 -0.69 4.5 100ms
2 -7.921206743602 -2.32 -1.52 1.0 52.4ms
3 -7.921407025940 -3.70 -2.49 1.5 64.0ms
4 -7.921440985965 -4.47 -2.84 2.4 70.4ms
5 -7.921441667266 -6.17 -3.04 1.0 52.7ms
6 -7.921442008366 -6.47 -4.58 1.1 54.2ms
7 -7.921442021880 -7.87 -4.66 3.0 86.9ms
8 -7.921442022134 -9.59 -5.37 1.1 54.6ms
9 -7.921442022139 -11.31 -5.38 1.8 61.3ms
10 -7.921442022144 -11.34 -6.05 1.0 53.5ms
11 -7.921442022144 -12.59 -6.77 1.5 64.3ms
12 -7.921442022144 -13.60 -7.05 2.0 65.8ms
13 -7.921442022144 -14.75 -7.96 1.1 55.5ms
14 -7.921442022144 + -Inf -8.10 2.2 70.2msNext 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
---- ------- ------ ---------- ------- ------ ---------------
73.1 1.92s Non-interacting
1 0 1 0.31 52.4 2.18s
2 0 2 -0.52 47.0 2.07s
3 0 3 -2.40 41.8 1.31s
4 0 4 -4.46 29.8 1.04s
5 0 5 -6.46 17.4 738ms
6 0 6 -8.91 4.0 416ms
7 1 1 -7.85 55.6 1.97s Restart
8 1 2 -8.92 5.6 450ms
72.8 1.98s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.82s Non-interacting
1 0 1 0.31 52.4 1.68s
2 0 2 -0.52 47.0 1.46s
3 0 3 -2.40 41.8 1.32s
4 0 4 -4.46 29.8 1.03s
5 0 5 -6.46 17.4 734ms
6 0 6 -8.91 4.0 422ms
7 1 1 -7.85 55.6 1.96s Restart
8 1 2 -8.92 5.6 449ms
72.8 1.96s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.81s Non-interacting
1 0 1 0.31 52.4 1.66s
2 0 2 -0.52 47.0 1.44s
3 0 3 -2.40 41.8 1.96s
4 0 4 -4.46 29.8 1.04s
5 0 5 -6.46 17.4 729ms
6 0 6 -8.91 4.0 411ms
7 1 1 -7.85 55.6 1.96s Restart
8 1 2 -8.92 5.6 461ms
72.9 1.96s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.1 1.81s Non-interacting
1 0 1 0.31 52.4 1.67s
2 0 2 -0.52 47.0 1.45s
3 0 3 -2.40 41.8 1.32s
4 0 4 -4.46 29.8 1.03s
5 0 5 -6.46 17.4 731ms
6 0 6 -8.91 4.0 410ms
7 1 1 -7.86 55.5 1.96s Restart
8 1 2 -8.97 5.5 441ms
72.8 1.95s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.1 1.79s Non-interacting
1 0 1 0.31 52.4 1.66s
2 0 2 -0.52 47.0 1.43s
3 0 3 -2.40 41.8 1.30s
4 0 4 -4.46 29.8 1.02s
5 0 5 -6.46 17.4 1.35s
6 0 6 -8.91 4.0 427ms
7 1 1 -7.86 55.5 1.93s Restart
8 1 2 -8.97 5.5 453ms
72.9 1.97s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.82s Non-interacting
1 0 1 0.31 52.4 1.68s
2 0 2 -0.52 47.0 1.45s
3 0 3 -2.40 41.8 1.32s
4 0 4 -4.46 29.8 1.04s
5 0 5 -6.46 17.4 737ms
6 0 6 -8.91 4.0 420ms
7 1 1 -7.86 55.5 1.96s Restart
8 1 2 -8.97 5.5 453ms
72.8 1.96s Final orbitals
86.454733 seconds (92.57 M allocations: 80.340 GiB, 6.86% gc time, 1.18% compilation time: 100% of which was recompilation)These are the final phonon frequencies:
phret_q0.frequencies6-element Vector{Float64}:
-0.00349815535903826
-0.002977451157750326
-0.002977451157451438
0.004302230620380276
0.004302230620605862
0.004353201752256856