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);
nothing # hiden Energy log10(ΔE) log10(Δρ) Diag Δtime
--- --------------- --------- --------- ---- ------
1 -7.916400691256 -0.69 4.8 109ms
2 -7.921198973371 -2.32 -1.52 1.0 54.9ms
3 -7.921399630753 -3.70 -2.49 1.2 57.9ms
4 -7.921440862374 -4.38 -2.79 2.5 77.6ms
5 -7.921441419687 -6.25 -2.89 1.1 90.0ms
6 -7.921442005617 -6.23 -4.48 1.0 55.6ms
7 -7.921442021430 -7.80 -4.44 3.0 85.4ms
8 -7.921442022117 -9.16 -5.23 1.0 56.0ms
9 -7.921442022141 -10.61 -5.43 1.5 61.9ms
10 -7.921442022143 -11.74 -5.90 1.1 59.3ms
11 -7.921442022144 -12.04 -6.31 1.1 84.7ms
12 -7.921442022144 -13.27 -6.48 1.4 221ms
13 -7.921442022144 -13.91 -7.22 1.0 57.2ms
14 -7.921442022144 -14.57 -7.21 1.8 118ms
15 -7.921442022144 -15.05 -7.69 1.0 57.9ms
16 -7.921442022144 + -14.57 -8.11 1.0 57.0ms
Next 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]);
nothing # hideIter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
20.0 2.77s Non-interacting
1 0 1 0.31 14.7 12.8s
2 0 2 -0.52 13.1 1.23s
3 0 3 -2.40 11.6 1.09s
4 0 4 -4.46 8.6 870ms
5 0 5 -6.46 5.1 624ms
6 0 6 -8.91 1.0 350ms
7 1 1 -7.82 16.5 1.85s Restart
8 1 2 -8.84 2.1 412ms
19.9 1.67s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
20.0 1.53s Non-interacting
1 0 1 0.31 14.7 1.42s
2 0 2 -0.52 13.1 1.21s
3 0 3 -2.40 11.6 1.13s
4 0 4 -4.46 8.6 885ms
5 0 5 -6.46 5.1 639ms
6 0 6 -8.91 1.0 360ms
7 1 1 -7.82 16.5 1.68s Restart
8 1 2 -8.84 2.1 396ms
19.9 1.63s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
20.0 1.52s Non-interacting
1 0 1 0.31 14.7 1.42s
2 0 2 -0.52 13.1 1.23s
3 0 3 -2.40 11.6 1.12s
4 0 4 -4.46 8.6 871ms
5 0 5 -6.46 5.1 634ms
6 0 6 -8.91 1.0 361ms
7 1 1 -7.82 16.5 2.42s Restart
8 1 2 -8.84 2.1 409ms
19.9 1.51s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
20.0 1.48s Non-interacting
1 0 1 0.31 14.7 1.38s
2 0 2 -0.52 13.1 1.21s
3 0 3 -2.40 11.6 1.12s
4 0 4 -4.46 8.6 863ms
5 0 5 -6.46 5.1 635ms
6 0 6 -8.91 1.0 359ms
7 1 1 -7.83 16.5 1.70s Restart
8 1 2 -8.84 2.1 396ms
19.9 1.63s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
20.0 1.54s Non-interacting
1 0 1 0.31 14.7 1.43s
2 0 2 -0.52 13.1 1.23s
3 0 3 -2.40 11.6 1.12s
4 0 4 -4.46 8.6 873ms
5 0 5 -6.46 5.1 636ms
6 0 6 -8.91 1.0 361ms
7 1 1 -7.83 16.5 1.68s Restart
8 1 2 -8.84 2.1 397ms
19.9 1.64s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
20.0 1.52s Non-interacting
1 0 1 0.31 14.7 1.43s
2 0 2 -0.52 13.1 1.23s
3 0 3 -2.40 11.6 1.12s
4 0 4 -4.46 8.6 878ms
5 0 5 -6.46 5.1 714ms
6 0 6 -8.91 1.0 1.03s
7 1 1 -7.83 16.5 1.62s Restart
8 1 2 -8.84 2.1 353ms
19.9 1.62s Final orbitals
106.924746 seconds (136.90 M allocations: 23.467 GiB, 4.23% gc time, 31.13% compilation time)
These are the final phonon frequencies:
phret_q0.frequencies6-element Vector{Float64}:
-0.00349815535744551
-0.002977451156881334
-0.002977451156336011
0.0043022306242041985
0.004302230624331132
0.004353201754680059