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 -7.916447684846 -0.69 4.8 106ms
2 -7.921207689548 -2.32 -1.52 1.0 54.7ms
3 -7.921403839682 -3.71 -2.49 1.4 63.1ms
4 -7.921440972429 -4.43 -2.82 2.8 77.7ms
5 -7.921441577043 -6.22 -2.97 1.1 56.0ms
6 -7.921442007883 -6.37 -4.49 1.0 55.4ms
7 -7.921442021794 -7.86 -4.60 2.9 87.8ms
8 -7.921442022128 -9.48 -5.31 1.0 54.6ms
9 -7.921442022142 -10.86 -5.66 1.6 61.6ms
10 -7.921442022144 -11.68 -5.90 1.1 56.8ms
11 -7.921442022144 -12.40 -6.63 1.1 61.7ms
12 -7.921442022144 -13.34 -7.95 2.1 70.1ms
13 -7.921442022144 + -Inf -7.83 3.1 86.1ms
14 -7.921442022144 -15.05 -8.03 1.0 58.8msNext 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 1.92s Non-interacting
1 0 1 0.31 52.4 2.17s
2 0 2 -0.52 46.8 2.08s
3 0 3 -2.40 41.7 1.29s
4 0 4 -4.46 29.6 1.03s
5 0 5 -6.46 17.4 739ms
6 0 6 -8.91 4.0 420ms
7 1 1 -7.81 55.6 1.97s Restart
8 1 2 -8.87 5.7 462ms
72.8 1.99s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
72.9 1.81s Non-interacting
1 0 1 0.31 52.4 1.67s
2 0 2 -0.52 46.8 1.44s
3 0 3 -2.40 41.7 1.33s
4 0 4 -4.46 29.6 1.04s
5 0 5 -6.46 17.4 745ms
6 0 6 -8.91 4.0 417ms
7 1 1 -7.81 55.6 1.99s Restart
8 1 2 -8.87 5.7 454ms
72.8 1.95s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
72.9 1.80s Non-interacting
1 0 1 0.31 52.4 1.68s
2 0 2 -0.52 46.8 1.45s
3 0 3 -2.40 41.7 2.00s
4 0 4 -4.46 29.6 1.01s
5 0 5 -6.46 17.4 729ms
6 0 6 -8.91 4.0 426ms
7 1 1 -7.81 55.6 2.02s Restart
8 1 2 -8.87 5.7 465ms
72.7 1.98s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.81s Non-interacting
1 0 1 0.31 52.4 1.67s
2 0 2 -0.52 46.8 1.45s
3 0 3 -2.40 41.7 1.34s
4 0 4 -4.46 29.6 1.05s
5 0 5 -6.46 17.4 751ms
6 0 6 -8.91 4.0 417ms
7 1 1 -7.81 55.6 2.00s Restart
8 1 2 -8.83 5.6 458ms
72.8 1.96s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
72.9 1.81s Non-interacting
1 0 1 0.31 52.4 1.68s
2 0 2 -0.52 46.8 1.46s
3 0 3 -2.40 41.7 1.35s
4 0 4 -4.46 29.6 1.03s
5 0 5 -6.46 17.4 1.41s
6 0 6 -8.91 4.0 432ms
7 1 1 -7.81 55.6 1.93s Restart
8 1 2 -8.83 5.6 460ms
72.8 1.94s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
72.9 1.81s Non-interacting
1 0 1 0.31 52.4 1.69s
2 0 2 -0.52 46.8 1.47s
3 0 3 -2.40 41.7 1.33s
4 0 4 -4.46 29.6 1.05s
5 0 5 -6.46 17.4 756ms
6 0 6 -8.91 4.0 421ms
7 1 1 -7.81 55.6 2.03s Restart
8 1 2 -8.83 5.6 460ms
72.7 1.95s Final orbitals
87.150660 seconds (92.41 M allocations: 79.890 GiB, 7.05% gc time, 1.19% compilation time: 100% of which was recompilation)These are the final phonon frequencies:
phret_q0.frequencies6-element Vector{Float64}:
-0.003498155360997445
-0.002977451158757403
-0.002977451158705866
0.004302230613751535
0.0043022306138964595
0.004353201746657406