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 -7.916455508180 -0.69 4.5 104ms
2 -7.921211011806 -2.32 -1.52 1.0 53.7ms
3 -7.921404649456 -3.71 -2.49 1.4 65.8ms
4 -7.921440957444 -4.44 -2.82 2.8 79.4ms
5 -7.921441615912 -6.18 -3.00 1.0 55.5ms
6 -7.921442008406 -6.41 -4.56 1.0 55.8ms
7 -7.921442021824 -7.87 -4.60 3.0 92.4ms
8 -7.921442022130 -9.51 -5.32 1.0 55.6ms
9 -7.921442022143 -10.91 -5.86 1.8 64.8ms
10 -7.921442022144 -11.96 -6.03 1.4 62.2ms
11 -7.921442022144 -12.67 -6.65 1.0 62.5ms
12 -7.921442022144 -13.65 -7.73 1.6 64.2ms
13 -7.921442022144 -14.57 -8.07 2.4 79.1msNext 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 1.97s Non-interacting
1 0 1 0.31 52.7 2.26s
2 0 2 -0.52 47.2 1.48s
3 0 3 -2.40 41.9 1.35s
4 0 4 -4.46 30.0 1.06s
5 0 5 -6.46 17.5 754ms
6 0 6 -8.91 4.0 418ms
7 1 1 -7.83 55.9 1.99s Restart
8 1 2 -9.04 5.6 466ms
72.8 2.79s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.83s Non-interacting
1 0 1 0.31 52.7 1.71s
2 0 2 -0.52 47.2 1.46s
3 0 3 -2.40 41.9 1.34s
4 0 4 -4.46 30.0 1.04s
5 0 5 -6.46 17.5 748ms
6 0 6 -8.91 4.0 415ms
7 1 1 -7.83 55.9 2.01s Restart
8 1 2 -9.04 5.6 458ms
72.8 1.98s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.82s Non-interacting
1 0 1 0.31 52.7 1.70s
2 0 2 -0.52 47.2 1.47s
3 0 3 -2.40 41.9 1.32s
4 0 4 -4.46 30.0 1.03s
5 0 5 -6.46 17.5 737ms
6 0 6 -8.91 4.0 415ms
7 1 1 -7.83 55.9 1.97s Restart
8 1 2 -9.04 5.6 450ms
72.8 1.97s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 2.67s Non-interacting
1 0 1 0.31 52.7 1.67s
2 0 2 -0.52 47.2 1.48s
3 0 3 -2.40 41.9 1.36s
4 0 4 -4.46 30.0 1.06s
5 0 5 -6.46 17.6 761ms
6 0 6 -8.91 4.0 426ms
7 1 1 -7.86 55.7 2.03s Restart
8 1 2 -9.15 5.6 462ms
72.8 2.01s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.85s Non-interacting
1 0 1 0.31 52.7 1.72s
2 0 2 -0.52 47.2 1.49s
3 0 3 -2.40 41.9 1.36s
4 0 4 -4.46 30.0 1.07s
5 0 5 -6.46 17.6 766ms
6 0 6 -8.91 4.0 426ms
7 1 1 -7.86 55.7 2.03s Restart
8 1 2 -9.15 5.6 457ms
72.8 1.99s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.82s Non-interacting
1 0 1 0.31 52.7 1.67s
2 0 2 -0.52 47.2 1.45s
3 0 3 -2.40 41.9 2.01s
4 0 4 -4.46 30.0 1.01s
5 0 5 -6.46 17.6 729ms
6 0 6 -8.91 4.0 419ms
7 1 1 -7.86 55.7 1.97s Restart
8 1 2 -9.15 5.6 456ms
72.8 1.94s Final orbitals
88.140004 seconds (91.86 M allocations: 80.063 GiB, 7.26% gc time, 1.23% compilation time: 100% of which was recompilation)These are the final phonon frequencies:
phret_q0.frequencies6-element Vector{Float64}:
-0.00349815535226618
-0.0029774511578562505
-0.002977451157619339
0.004302230654362398
0.00430223065456459
0.0043532017813520864