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);
nothing # hiden Energy log10(ΔE) log10(Δρ) Diag Δtime
--- --------------- --------- --------- ---- ------
1 -7.916423666610 -0.69 4.8 167ms
2 -7.921206361341 -2.32 -1.52 1.0 60.3ms
3 -7.921402683565 -3.71 -2.49 1.2 64.0ms
4 -7.921440892003 -4.42 -2.81 2.4 83.1ms
5 -7.921441523412 -6.20 -2.94 1.0 60.2ms
6 -7.921442006823 -6.32 -4.48 1.0 59.4ms
7 -7.921442021502 -7.83 -4.46 3.0 94.9ms
8 -7.921442022120 -9.21 -5.30 1.0 64.8ms
9 -7.921442022143 -10.65 -5.69 1.6 72.9ms
10 -7.921442022144 -12.08 -6.10 1.4 72.1ms
11 -7.921442022144 -12.38 -6.73 1.2 69.5ms
12 -7.921442022144 -13.51 -6.96 1.9 75.9ms
13 -7.921442022144 -14.75 -7.58 1.0 89.2ms
14 -7.921442022144 + -Inf -7.90 1.5 67.9ms
15 -7.921442022144 + -15.05 -8.61 1.1 62.8ms
Next 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]);
nothing # hideIter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
20.0 2.04s Non-interacting
1 0 1 0.31 14.7 13.6s
2 0 2 -0.52 13.1 1.27s
3 0 3 -2.40 11.6 1.13s
4 0 4 -4.46 8.6 910ms
5 0 5 -6.46 5.1 648ms
6 0 6 -8.91 1.0 359ms
7 1 1 -7.82 16.5 1.92s Restart
8 1 2 -8.84 2.1 424ms
18.6 2.29s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
20.0 1.61s Non-interacting
1 0 1 0.31 14.7 2.32s
2 0 2 -0.52 13.1 1.15s
3 0 3 -2.40 11.6 1.04s
4 0 4 -4.46 8.6 856ms
5 0 5 -6.46 5.1 612ms
6 0 6 -8.91 1.0 350ms
7 1 1 -7.82 16.5 1.65s Restart
8 1 2 -8.84 2.1 379ms
18.6 1.63s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
20.0 1.60s Non-interacting
1 0 1 0.31 14.7 1.45s
2 0 2 -0.52 13.1 1.22s
3 0 3 -2.40 11.6 1.17s
4 0 4 -4.46 8.6 871ms
5 0 5 -6.46 5.1 653ms
6 0 6 -8.91 1.0 360ms
7 1 1 -7.82 16.5 1.73s Restart
8 1 2 -8.84 2.1 411ms
18.6 1.68s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
20.0 1.59s Non-interacting
1 0 1 0.31 14.7 1.46s
2 0 2 -0.52 13.1 1.25s
3 0 3 -2.40 11.6 1.16s
4 0 4 -4.46 8.6 917ms
5 0 5 -6.46 5.1 656ms
6 0 6 -8.91 1.0 371ms
7 1 1 -7.83 16.5 1.74s Restart
8 1 2 -8.87 2.1 480ms
18.6 2.35s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
20.0 1.47s Non-interacting
1 0 1 0.31 14.7 1.42s
2 0 2 -0.52 13.1 1.19s
3 0 3 -2.40 11.6 1.12s
4 0 4 -4.46 8.6 889ms
5 0 5 -6.46 5.1 651ms
6 0 6 -8.91 1.0 349ms
7 1 1 -7.83 16.5 1.70s Restart
8 1 2 -8.87 2.1 417ms
18.6 1.60s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
20.0 1.60s Non-interacting
1 0 1 0.31 14.7 1.44s
2 0 2 -0.52 13.1 1.27s
3 0 3 -2.40 11.6 1.13s
4 0 4 -4.46 8.6 912ms
5 0 5 -6.46 5.1 647ms
6 0 6 -8.91 1.0 366ms
7 1 1 -7.83 16.5 1.73s Restart
8 1 2 -8.87 2.1 414ms
18.6 1.66s Final orbitals
110.843711 seconds (137.48 M allocations: 23.450 GiB, 4.23% gc time, 32.05% compilation time)
These are the final phonon frequencies:
phret_q0.frequencies6-element Vector{Float64}:
-0.00349815535456781
-0.0029774511552699513
-0.0029774511551703005
0.004302230632495941
0.004302230632502189
0.004353201762861478