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 -7.916421912380 -0.69 4.8 109ms
2 -7.921201736048 -2.32 -1.52 1.0 54.8ms
3 -7.921403779909 -3.69 -2.49 1.5 59.8ms
4 -7.921440779818 -4.43 -2.82 2.5 75.2ms
5 -7.921441573806 -6.10 -2.97 1.2 57.4ms
6 -7.921442004811 -6.37 -4.41 1.0 54.6ms
7 -7.921442021706 -7.77 -4.55 2.8 100ms
8 -7.921442022123 -9.38 -5.16 1.0 57.6ms
9 -7.921442022143 -10.71 -5.87 1.5 63.6ms
10 -7.921442022144 -11.94 -5.86 1.9 69.8ms
11 -7.921442022144 -12.39 -6.55 1.0 59.1ms
12 -7.921442022144 -13.65 -7.30 1.1 60.7ms
13 -7.921442022144 -14.75 -7.56 2.0 73.6ms
14 -7.921442022144 + -15.05 -8.79 1.1 62.5msNext 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 2.00s Non-interacting
1 0 1 0.31 52.4 3.66s
2 0 2 -0.52 47.0 1.31s
3 0 3 -2.40 41.7 1.20s
4 0 4 -4.46 29.7 972ms
5 0 5 -6.46 17.4 721ms
6 0 6 -8.91 4.0 420ms
7 1 1 -7.84 55.5 1.89s Restart
8 1 2 -8.97 5.6 458ms
72.8 1.75s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.58s Non-interacting
1 0 1 0.31 52.4 1.52s
2 0 2 -0.52 47.0 1.31s
3 0 3 -2.40 41.7 1.21s
4 0 4 -4.46 29.7 975ms
5 0 5 -6.46 17.4 713ms
6 0 6 -8.91 4.0 420ms
7 1 1 -7.84 55.5 1.84s Restart
8 1 2 -8.97 5.6 451ms
72.8 1.74s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
72.9 1.57s Non-interacting
1 0 1 0.31 52.4 1.53s
2 0 2 -0.52 47.0 1.32s
3 0 3 -2.40 41.7 1.22s
4 0 4 -4.46 29.7 966ms
5 0 5 -6.46 17.4 710ms
6 0 6 -8.91 4.0 425ms
7 1 1 -7.84 55.5 1.85s Restart
8 1 2 -8.97 5.6 466ms
72.7 1.75s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.60s Non-interacting
1 0 1 0.31 52.4 1.56s
2 0 2 -0.52 47.0 2.51s
3 0 3 -2.40 41.7 1.37s
4 0 4 -4.46 29.7 915ms
5 0 5 -6.46 17.4 700ms
6 0 6 -8.91 4.0 434ms
7 1 1 -7.84 55.4 1.84s Restart
8 1 2 -9.00 5.6 464ms
72.7 1.73s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
72.9 1.57s Non-interacting
1 0 1 0.31 52.4 1.54s
2 0 2 -0.52 47.0 1.31s
3 0 3 -2.40 41.7 1.21s
4 0 4 -4.46 29.7 980ms
5 0 5 -6.46 17.4 698ms
6 0 6 -8.91 4.0 418ms
7 1 1 -7.84 55.4 1.85s Restart
8 1 2 -9.00 5.6 469ms
72.7 1.72s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
72.9 1.59s Non-interacting
1 0 1 0.31 52.4 1.54s
2 0 2 -0.52 47.0 1.33s
3 0 3 -2.40 41.7 1.25s
4 0 4 -4.46 29.7 957ms
5 0 5 -6.46 17.4 700ms
6 0 6 -8.91 4.0 420ms
7 1 1 -7.84 55.4 1.84s Restart
8 1 2 -9.00 5.6 466ms
72.7 1.73s Final orbitals
85.635723 seconds (101.40 M allocations: 80.325 GiB, 7.16% gc time, 8.34% compilation time: 100% of which was recompilation)These are the final phonon frequencies:
phret_q0.frequencies6-element Vector{Float64}:
-0.003498155361767803
-0.002977451163613997
-0.0029774511634847733
0.004302230624195357
0.004302230624457564
0.00435320175543643