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 -7.916454152220 -0.69 4.8 109ms
2 -7.921208997004 -2.32 -1.52 1.0 52.5ms
3 -7.921405199455 -3.71 -2.49 1.5 58.2ms
4 -7.921440940362 -4.45 -2.83 2.5 73.5ms
5 -7.921441594597 -6.18 -2.99 1.1 56.6ms
6 -7.921442005989 -6.39 -4.48 1.0 57.6ms
7 -7.921442021773 -7.80 -4.57 3.1 85.0ms
8 -7.921442022128 -9.45 -5.22 1.0 54.1ms
9 -7.921442022138 -10.96 -5.32 1.4 58.4ms
10 -7.921442022144 -11.28 -5.96 1.0 59.4ms
11 -7.921442022144 -12.40 -7.29 1.4 57.7ms
12 -7.921442022144 -13.55 -6.79 2.9 81.9ms
13 -7.921442022144 -14.27 -7.57 1.0 56.0ms
14 -7.921442022144 + -15.05 -8.36 1.1 68.6msNext 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
---- ------- ------ ---------- ------- ------ ---------------
72.9 2.59s Non-interacting
1 0 1 0.31 52.3 2.16s
2 0 2 -0.52 46.9 1.45s
3 0 3 -2.40 41.6 1.32s
4 0 4 -4.46 29.6 1.02s
5 0 5 -6.46 17.4 737ms
6 0 6 -8.91 4.0 409ms
7 1 1 -7.83 55.5 1.97s Restart
8 1 2 -8.89 5.6 454ms
72.7 1.94s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
72.9 1.81s Non-interacting
1 0 1 0.31 52.3 1.67s
2 0 2 -0.52 46.9 1.43s
3 0 3 -2.40 41.6 1.30s
4 0 4 -4.46 29.6 1.02s
5 0 5 -6.46 17.4 731ms
6 0 6 -8.91 4.0 415ms
7 1 1 -7.83 55.5 1.95s Restart
8 1 2 -8.89 5.6 450ms
72.7 1.94s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
72.9 1.79s Non-interacting
1 0 1 0.31 52.3 1.65s
2 0 2 -0.52 46.9 2.12s
3 0 3 -2.40 41.6 1.28s
4 0 4 -4.46 29.6 1.03s
5 0 5 -6.46 17.4 727ms
6 0 6 -8.91 4.0 420ms
7 1 1 -7.83 55.5 1.95s Restart
8 1 2 -8.89 5.6 447ms
72.7 1.97s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
72.9 1.81s Non-interacting
1 0 1 0.31 52.3 1.66s
2 0 2 -0.52 46.9 1.45s
3 0 3 -2.40 41.6 1.32s
4 0 4 -4.46 29.6 1.03s
5 0 5 -6.46 17.4 729ms
6 0 6 -8.91 4.0 412ms
7 1 1 -7.83 55.5 1.96s Restart
8 1 2 -8.89 5.6 446ms
72.7 1.95s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
72.9 1.80s Non-interacting
1 0 1 0.31 52.3 1.65s
2 0 2 -0.52 46.9 1.42s
3 0 3 -2.40 41.6 1.29s
4 0 4 -4.46 29.6 1.70s
5 0 5 -6.46 17.4 731ms
6 0 6 -8.91 4.0 402ms
7 1 1 -7.83 55.5 1.98s Restart
8 1 2 -8.89 5.6 459ms
72.7 1.95s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
72.9 1.81s Non-interacting
1 0 1 0.31 52.3 1.66s
2 0 2 -0.52 46.9 1.44s
3 0 3 -2.40 41.6 1.30s
4 0 4 -4.46 29.6 1.02s
5 0 5 -6.46 17.4 733ms
6 0 6 -8.91 4.0 408ms
7 1 1 -7.83 55.5 1.96s Restart
8 1 2 -8.89 5.6 444ms
72.7 1.94s Final orbitals
86.178965 seconds (92.51 M allocations: 80.234 GiB, 7.18% gc time, 1.18% compilation time: 100% of which was recompilation)These are the final phonon frequencies:
phret_q0.frequencies6-element Vector{Float64}:
-0.0034981553549682243
-0.0029774511578985054
-0.002977451157775467
0.004302230641911374
0.004302230642162484
0.004353201769536378