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 -7.916421987781 -0.69 4.9 113ms
2 -7.921207197869 -2.32 -1.52 1.0 55.9ms
3 -7.921409380983 -3.69 -2.49 1.5 62.7ms
4 -7.921441004885 -4.50 -2.86 2.5 77.4ms
5 -7.921441764445 -6.12 -3.14 1.1 72.4ms
6 -7.921442010091 -6.61 -4.52 1.1 58.5ms
7 -7.921442021984 -7.92 -4.85 2.4 79.5ms
8 -7.921442022136 -9.82 -5.39 1.1 59.5ms
9 -7.921442022143 -11.15 -5.39 1.8 65.8ms
10 -7.921442022144 -11.96 -6.38 1.0 58.0ms
11 -7.921442022144 -12.91 -7.37 1.9 79.2ms
12 -7.921442022144 -14.21 -8.41 2.4 78.8msNext 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
---- ------- ------ ---------- ------- ------ ---------------
73.1 2.42s Non-interacting
1 0 1 0.31 52.9 4.07s
2 0 2 -0.52 47.2 1.58s
3 0 3 -2.40 42.0 1.43s
4 0 4 -4.46 30.0 1.12s
5 0 5 -6.46 17.6 800ms
6 0 6 -8.91 4.0 450ms
7 1 1 -7.88 55.6 2.18s Restart
8 1 2 -9.08 5.5 482ms
72.9 2.13s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.98s Non-interacting
1 0 1 0.31 52.9 1.83s
2 0 2 -0.52 47.2 1.58s
3 0 3 -2.40 42.0 1.43s
4 0 4 -4.46 30.0 1.15s
5 0 5 -6.46 17.6 800ms
6 0 6 -8.91 4.0 443ms
7 1 1 -7.88 55.6 2.13s Restart
8 1 2 -9.08 5.5 477ms
72.9 2.13s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 3.48s Non-interacting
1 0 1 0.31 52.9 1.81s
2 0 2 -0.52 47.2 1.56s
3 0 3 -2.40 42.0 1.43s
4 0 4 -4.46 30.0 1.13s
5 0 5 -6.46 17.6 795ms
6 0 6 -8.91 4.0 445ms
7 1 1 -7.88 55.6 2.15s Restart
8 1 2 -9.08 5.5 478ms
72.8 2.12s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.1 2.00s Non-interacting
1 0 1 0.31 52.9 1.83s
2 0 2 -0.52 47.2 1.59s
3 0 3 -2.40 42.0 1.45s
4 0 4 -4.46 30.0 1.12s
5 0 5 -6.46 17.6 797ms
6 0 6 -8.91 4.0 446ms
7 1 1 -7.88 55.5 2.13s Restart
8 1 2 -9.22 5.4 482ms
72.9 2.15s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.1 1.99s Non-interacting
1 0 1 0.31 52.9 1.81s
2 0 2 -0.52 47.2 1.56s
3 0 3 -2.40 42.0 1.43s
4 0 4 -4.46 30.0 1.12s
5 0 5 -6.46 17.6 778ms
6 0 6 -8.91 4.0 444ms
7 1 1 -7.88 55.5 2.12s Restart
8 1 2 -9.22 5.4 483ms
72.9 2.12s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.96s Non-interacting
1 0 1 0.31 52.9 1.79s
2 0 2 -0.52 47.2 1.55s
3 0 3 -2.40 42.0 1.40s
4 0 4 -4.46 30.0 2.52s
5 0 5 -6.46 17.6 724ms
6 0 6 -8.91 4.0 430ms
7 1 1 -7.88 55.5 2.03s Restart
8 1 2 -9.22 5.4 485ms
72.9 2.14s Final orbitals
100.230389 seconds (101.57 M allocations: 80.572 GiB, 8.16% gc time, 7.53% compilation time: 100% of which was recompilation)These are the final phonon frequencies:
phret_q0.frequencies6-element Vector{Float64}:
-0.0034981553539986166
-0.0029774511549183337
-0.002977451154315081
0.004302230629945645
0.004302230630781423
0.004353201760846797