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 -7.916444498671 -0.69 4.6 104ms
2 -7.921209994689 -2.32 -1.52 1.0 50.7ms
3 -7.921404980662 -3.71 -2.49 1.4 54.5ms
4 -7.921440967947 -4.44 -2.82 2.6 70.8ms
5 -7.921441631478 -6.18 -3.00 1.1 57.5ms
6 -7.921442007657 -6.42 -4.55 1.0 51.1ms
7 -7.921442021854 -7.85 -4.63 2.9 77.2ms
8 -7.921442022128 -9.56 -5.29 1.0 51.7ms
9 -7.921442022143 -10.81 -6.15 1.6 63.0ms
10 -7.921442022144 -12.26 -6.04 2.4 69.4ms
11 -7.921442022144 -12.75 -6.62 1.0 52.5ms
12 -7.921442022144 -14.10 -7.18 1.1 52.9ms
13 -7.921442022144 -14.35 -7.43 1.2 56.1ms
14 -7.921442022144 + -14.75 -8.27 1.1 58.2msNext 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
---- ------- ------ ---------- ------- ------ ---------------
72.9 1.89s Non-interacting
1 0 1 0.31 52.5 2.84s
2 0 2 -0.52 47.0 1.39s
3 0 3 -2.40 41.7 1.29s
4 0 4 -4.46 29.6 997ms
5 0 5 -6.46 17.4 721ms
6 0 6 -8.91 4.0 397ms
7 1 1 -7.82 55.5 1.92s Restart
8 1 2 -8.90 5.5 432ms
72.7 1.93s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
72.9 1.80s Non-interacting
1 0 1 0.31 52.5 1.67s
2 0 2 -0.52 47.0 1.43s
3 0 3 -2.40 41.7 1.31s
4 0 4 -4.46 29.6 1.02s
5 0 5 -6.46 17.4 724ms
6 0 6 -8.91 4.0 404ms
7 1 1 -7.82 55.5 1.93s Restart
8 1 2 -8.90 5.5 439ms
72.7 1.92s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
72.9 1.78s Non-interacting
1 0 1 0.31 52.5 1.64s
2 0 2 -0.52 47.0 1.42s
3 0 3 -2.40 41.7 2.04s
4 0 4 -4.46 29.6 1.03s
5 0 5 -6.46 17.4 714ms
6 0 6 -8.91 4.0 401ms
7 1 1 -7.82 55.5 1.96s Restart
8 1 2 -8.90 5.5 442ms
72.8 1.95s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.81s Non-interacting
1 0 1 0.31 52.5 1.66s
2 0 2 -0.52 47.0 1.42s
3 0 3 -2.40 41.7 1.29s
4 0 4 -4.46 29.6 1.02s
5 0 5 -6.46 17.4 725ms
6 0 6 -8.91 4.0 413ms
7 1 1 -7.81 55.6 1.95s Restart
8 1 2 -8.87 5.5 444ms
72.7 1.94s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
72.9 1.81s Non-interacting
1 0 1 0.31 52.5 1.68s
2 0 2 -0.52 47.0 1.45s
3 0 3 -2.40 41.7 1.32s
4 0 4 -4.46 29.6 1.02s
5 0 5 -6.46 17.4 727ms
6 0 6 -8.91 4.0 1.13s
7 1 1 -7.81 55.6 1.95s Restart
8 1 2 -8.87 5.5 435ms
72.7 1.96s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.82s Non-interacting
1 0 1 0.31 52.5 1.68s
2 0 2 -0.52 47.0 1.45s
3 0 3 -2.40 41.7 1.33s
4 0 4 -4.46 29.6 1.03s
5 0 5 -6.46 17.4 731ms
6 0 6 -8.91 4.0 409ms
7 1 1 -7.81 55.6 1.97s Restart
8 1 2 -8.87 5.5 443ms
72.8 1.95s Final orbitals
85.966155 seconds (91.75 M allocations: 79.896 GiB, 7.59% gc time, 1.23% compilation time: 100% of which was recompilation)These are the final phonon frequencies:
phret_q0.frequencies6-element Vector{Float64}:
-0.0034981553603667674
-0.0029774511634283875
-0.0029774511628361208
0.004302230632567693
0.004302230633013164
0.004353201764570384