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 -7.916441061112 -0.69 4.8 104ms
2 -7.921206181712 -2.32 -1.52 1.0 53.6ms
3 -7.921405805683 -3.70 -2.49 1.5 63.8ms
4 -7.921440958137 -4.45 -2.84 2.5 72.9ms
5 -7.921441632298 -6.17 -3.01 1.0 53.9ms
6 -7.921442006933 -6.43 -4.51 1.1 55.2ms
7 -7.921442021820 -7.83 -4.62 3.0 82.1ms
8 -7.921442022130 -9.51 -5.26 1.0 60.7ms
9 -7.921442022125 + -11.36 -4.97 2.0 64.9ms
10 -7.921442022143 -10.74 -5.83 1.0 54.5ms
11 -7.921442022144 -12.08 -7.08 1.5 59.5ms
12 -7.921442022144 -13.29 -6.62 2.9 84.5ms
13 -7.921442022144 -14.10 -8.25 1.0 54.7msNext 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 1.95s Non-interacting
1 0 1 0.31 52.4 2.23s
2 0 2 -0.52 47.1 1.48s
3 0 3 -2.40 41.7 1.34s
4 0 4 -4.46 29.7 1.05s
5 0 5 -6.46 17.4 750ms
6 0 6 -8.91 4.0 422ms
7 1 1 -7.85 55.5 2.01s Restart
8 1 2 -8.91 5.5 1.19s
72.8 1.94s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
72.9 1.85s Non-interacting
1 0 1 0.31 52.4 1.72s
2 0 2 -0.52 47.1 1.48s
3 0 3 -2.40 41.7 1.35s
4 0 4 -4.46 29.7 1.05s
5 0 5 -6.46 17.4 750ms
6 0 6 -8.91 4.0 417ms
7 1 1 -7.85 55.5 2.02s Restart
8 1 2 -8.91 5.5 454ms
72.8 1.98s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
72.9 1.83s Non-interacting
1 0 1 0.31 52.4 1.71s
2 0 2 -0.52 47.1 1.47s
3 0 3 -2.40 41.7 1.34s
4 0 4 -4.46 29.7 1.06s
5 0 5 -6.46 17.4 744ms
6 0 6 -8.91 4.0 419ms
7 1 1 -7.85 55.5 2.00s Restart
8 1 2 -8.91 5.5 453ms
72.8 1.97s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 2.52s Non-interacting
1 0 1 0.31 52.4 1.68s
2 0 2 -0.52 47.1 1.47s
3 0 3 -2.40 41.7 1.34s
4 0 4 -4.46 29.7 1.05s
5 0 5 -6.46 17.4 746ms
6 0 6 -8.91 4.0 422ms
7 1 1 -7.85 55.5 2.02s Restart
8 1 2 -8.91 5.5 457ms
72.8 1.99s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.84s Non-interacting
1 0 1 0.31 52.4 1.70s
2 0 2 -0.52 47.1 1.46s
3 0 3 -2.40 41.7 1.33s
4 0 4 -4.46 29.7 1.05s
5 0 5 -6.46 17.4 738ms
6 0 6 -8.91 4.0 416ms
7 1 1 -7.85 55.5 2.00s Restart
8 1 2 -8.91 5.5 449ms
72.8 1.96s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.82s Non-interacting
1 0 1 0.31 52.4 1.68s
2 0 2 -0.52 47.1 1.45s
3 0 3 -2.40 41.7 2.04s
4 0 4 -4.46 29.7 1.01s
5 0 5 -6.46 17.4 746ms
6 0 6 -8.91 4.0 419ms
7 1 1 -7.85 55.5 2.00s Restart
8 1 2 -8.91 5.5 450ms
72.7 1.98s Final orbitals
87.884219 seconds (91.77 M allocations: 79.895 GiB, 7.28% gc time, 1.18% compilation time: 100% of which was recompilation)These are the final phonon frequencies:
phret_q0.frequencies6-element Vector{Float64}:
-0.0034981553767579996
-0.0029774511810795505
-0.002977451180827274
0.004302230609488668
0.004302230610278128
0.0043532017382408895