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 -7.916428680021 -0.69 5.0 124ms
2 -7.921200727955 -2.32 -1.52 1.0 55.5ms
3 -7.921404085716 -3.69 -2.49 1.4 60.4ms
4 -7.921440921932 -4.43 -2.82 2.5 77.0ms
5 -7.921441581941 -6.18 -2.98 1.1 57.5ms
6 -7.921442007561 -6.37 -4.56 1.0 56.0ms
7 -7.921442021654 -7.85 -4.52 2.9 97.3ms
8 -7.921442022127 -9.32 -5.33 1.0 56.8ms
9 -7.921442022141 -10.86 -5.66 2.0 69.3ms
10 -7.921442022144 -11.61 -5.92 1.0 57.3ms
11 -7.921442022144 -12.43 -7.16 1.0 58.1ms
12 -7.921442022144 -13.53 -7.73 2.5 80.1ms
13 -7.921442022144 -14.57 -7.94 1.8 75.8ms
14 -7.921442022144 + -14.75 -8.43 1.0 57.0msNext 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 52.7 3.61s
2 0 2 -0.52 47.2 1.33s
3 0 3 -2.40 41.8 1.20s
4 0 4 -4.46 29.9 954ms
5 0 5 -6.46 17.6 692ms
6 0 6 -8.92 4.0 419ms
7 1 1 -7.88 55.6 1.85s Restart
8 1 2 -9.07 5.4 452ms
72.9 1.72s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.57s Non-interacting
1 0 1 0.31 52.7 1.51s
2 0 2 -0.52 47.2 1.32s
3 0 3 -2.40 41.8 1.19s
4 0 4 -4.46 29.9 941ms
5 0 5 -6.46 17.6 694ms
6 0 6 -8.92 4.0 412ms
7 1 1 -7.88 55.6 3.04s Restart
8 1 2 -9.07 5.4 411ms
72.8 1.80s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.54s Non-interacting
1 0 1 0.31 52.7 1.52s
2 0 2 -0.52 47.2 1.32s
3 0 3 -2.40 41.8 1.20s
4 0 4 -4.46 29.9 959ms
5 0 5 -6.46 17.6 698ms
6 0 6 -8.92 4.0 413ms
7 1 1 -7.88 55.6 1.82s Restart
8 1 2 -9.07 5.4 465ms
72.9 1.75s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.58s Non-interacting
1 0 1 0.31 52.7 1.55s
2 0 2 -0.52 47.2 1.32s
3 0 3 -2.40 41.9 1.21s
4 0 4 -4.46 29.9 958ms
5 0 5 -6.46 17.5 708ms
6 0 6 -8.92 4.0 421ms
7 1 1 -7.89 55.5 1.84s Restart
8 1 2 -9.09 5.4 455ms
72.9 1.73s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.58s Non-interacting
1 0 1 0.31 52.7 1.55s
2 0 2 -0.52 47.2 1.32s
3 0 3 -2.40 41.9 1.21s
4 0 4 -4.46 29.9 959ms
5 0 5 -6.46 17.5 712ms
6 0 6 -8.92 4.0 425ms
7 1 1 -7.89 55.5 1.81s Restart
8 1 2 -9.09 5.4 459ms
72.9 1.73s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.57s Non-interacting
1 0 1 0.31 52.7 1.53s
2 0 2 -0.52 47.2 1.31s
3 0 3 -2.40 41.9 1.20s
4 0 4 -4.46 29.9 953ms
5 0 5 -6.46 17.5 930ms
6 0 6 -8.92 4.0 1.56s
7 1 1 -7.89 55.5 1.95s Restart
8 1 2 -9.09 5.4 420ms
72.9 1.73s Final orbitals
86.511626 seconds (101.45 M allocations: 80.467 GiB, 8.07% gc time, 8.23% compilation time: 100% of which was recompilation)These are the final phonon frequencies:
phret_q0.frequencies6-element Vector{Float64}:
-0.003498155356790449
-0.0029774511589978157
-0.0029774511586413525
0.0043022306356310935
0.004302230635768646
0.00435320176561137