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 -7.916453300739 -0.69 4.6 106ms
2 -7.921210532563 -2.32 -1.52 1.0 54.4ms
3 -7.921405952197 -3.71 -2.49 1.5 59.5ms
4 -7.921440972127 -4.46 -2.83 2.5 86.4ms
5 -7.921441649930 -6.17 -3.02 1.1 56.8ms
6 -7.921442009221 -6.44 -4.58 1.1 56.1ms
7 -7.921442021942 -7.90 -4.72 3.0 86.0ms
8 -7.921442022133 -9.72 -5.47 1.0 55.6ms
9 -7.921442022137 -11.50 -5.19 1.8 65.3ms
10 -7.921442022144 -11.14 -6.17 1.0 67.3ms
11 -7.921442022144 -12.60 -7.00 1.8 64.0ms
12 -7.921442022144 -13.85 -7.19 2.1 71.4ms
13 -7.921442022144 + -14.75 -7.72 1.0 57.3ms
14 -7.921442022144 + -Inf -8.09 1.2 60.7msNext 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 2.43s Non-interacting
1 0 1 0.31 52.5 4.04s
2 0 2 -0.52 46.9 1.59s
3 0 3 -2.40 41.7 1.45s
4 0 4 -4.46 29.7 1.14s
5 0 5 -6.46 17.5 791ms
6 0 6 -8.91 4.0 442ms
7 1 1 -7.80 56.0 2.22s Restart
8 1 2 -8.74 5.7 1.98s
72.8 2.19s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
72.9 1.91s Non-interacting
1 0 1 0.31 52.5 1.80s
2 0 2 -0.52 46.9 1.57s
3 0 3 -2.40 41.7 1.45s
4 0 4 -4.46 29.7 1.11s
5 0 5 -6.46 17.5 796ms
6 0 6 -8.91 4.0 439ms
7 1 1 -7.80 56.0 2.14s Restart
8 1 2 -8.74 5.7 481ms
72.8 2.16s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 2.00s Non-interacting
1 0 1 0.31 52.5 1.83s
2 0 2 -0.52 46.9 1.60s
3 0 3 -2.40 41.7 1.43s
4 0 4 -4.46 29.7 1.13s
5 0 5 -6.46 17.5 816ms
6 0 6 -8.91 4.0 442ms
7 1 1 -7.80 56.0 2.15s Restart
8 1 2 -8.74 5.7 478ms
72.8 2.13s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.97s Non-interacting
1 0 1 0.31 52.5 1.81s
2 0 2 -0.52 46.9 1.58s
3 0 3 -2.40 41.7 1.43s
4 0 4 -4.46 29.7 1.13s
5 0 5 -6.46 17.5 801ms
6 0 6 -8.91 4.0 435ms
7 1 1 -7.80 56.0 2.16s Restart
8 1 2 -8.75 5.7 494ms
72.8 3.54s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.87s Non-interacting
1 0 1 0.31 52.5 1.79s
2 0 2 -0.52 46.9 1.55s
3 0 3 -2.40 41.7 1.41s
4 0 4 -4.46 29.7 1.10s
5 0 5 -6.46 17.5 786ms
6 0 6 -8.91 4.0 428ms
7 1 1 -7.80 56.0 2.12s Restart
8 1 2 -8.75 5.7 501ms
72.8 2.10s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.96s Non-interacting
1 0 1 0.31 52.5 1.81s
2 0 2 -0.52 46.9 1.59s
3 0 3 -2.40 41.7 1.43s
4 0 4 -4.46 29.7 1.12s
5 0 5 -6.46 17.5 795ms
6 0 6 -8.91 4.0 445ms
7 1 1 -7.80 56.0 2.14s Restart
8 1 2 -8.75 5.7 484ms
72.8 2.10s Final orbitals
100.357543 seconds (101.51 M allocations: 80.473 GiB, 8.22% gc time, 7.46% compilation time: 100% of which was recompilation)These are the final phonon frequencies:
phret_q0.frequencies6-element Vector{Float64}:
-0.003498155353281487
-0.00297745115099812
-0.002977451150687266
0.004302230622402073
0.004302230622466645
0.004353201755018048