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 -7.916428963766 -0.69 4.9 112ms
2 -7.921206146301 -2.32 -1.52 1.0 55.3ms
3 -7.921405441312 -3.70 -2.49 1.4 57.5ms
4 -7.921440942806 -4.45 -2.83 2.5 74.1ms
5 -7.921441604380 -6.18 -2.98 1.1 54.5ms
6 -7.921442007858 -6.39 -4.51 1.0 53.1ms
7 -7.921442021677 -7.86 -4.54 2.8 90.9ms
8 -7.921442022125 -9.35 -5.35 1.0 54.2ms
9 -7.921442022143 -10.74 -5.98 1.6 61.3ms
10 -7.921442022144 -12.18 -6.13 1.6 62.6ms
11 -7.921442022144 -12.63 -6.91 1.0 54.6ms
12 -7.921442022144 -13.97 -7.17 1.6 62.0ms
13 -7.921442022144 + -Inf -7.87 1.0 64.3ms
14 -7.921442022144 + -14.75 -8.13 1.6 62.8msNext 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 2.01s Non-interacting
1 0 1 0.31 52.4 3.69s
2 0 2 -0.52 46.9 1.29s
3 0 3 -2.40 41.6 1.20s
4 0 4 -4.46 29.6 938ms
5 0 5 -6.46 17.4 678ms
6 0 6 -8.91 4.0 412ms
7 1 1 -7.80 55.7 1.87s Restart
8 1 2 -8.83 5.7 469ms
72.7 1.74s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
72.9 1.58s Non-interacting
1 0 1 0.31 52.4 1.53s
2 0 2 -0.52 46.9 1.31s
3 0 3 -2.40 41.6 1.19s
4 0 4 -4.46 29.6 950ms
5 0 5 -6.46 17.4 699ms
6 0 6 -8.91 4.0 416ms
7 1 1 -7.80 55.7 3.37s Restart
8 1 2 -8.83 5.7 412ms
72.7 1.66s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
72.9 1.56s Non-interacting
1 0 1 0.31 52.4 1.49s
2 0 2 -0.52 46.9 1.30s
3 0 3 -2.40 41.6 1.18s
4 0 4 -4.46 29.6 937ms
5 0 5 -6.46 17.4 690ms
6 0 6 -8.91 4.0 399ms
7 1 1 -7.80 55.7 1.79s Restart
8 1 2 -8.83 5.7 446ms
72.7 1.71s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
72.9 1.59s Non-interacting
1 0 1 0.31 52.4 1.51s
2 0 2 -0.52 46.9 1.30s
3 0 3 -2.40 41.6 1.20s
4 0 4 -4.46 29.6 964ms
5 0 5 -6.46 17.4 698ms
6 0 6 -8.91 4.0 414ms
7 1 1 -7.79 55.7 1.85s Restart
8 1 2 -8.84 5.7 464ms
72.7 1.76s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
72.9 1.59s Non-interacting
1 0 1 0.31 52.4 1.52s
2 0 2 -0.52 46.9 1.33s
3 0 3 -2.40 41.6 1.20s
4 0 4 -4.46 29.6 984ms
5 0 5 -6.46 17.4 693ms
6 0 6 -8.91 4.0 415ms
7 1 1 -7.79 55.7 1.83s Restart
8 1 2 -8.84 5.7 456ms
72.7 1.76s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
72.9 1.60s Non-interacting
1 0 1 0.31 52.4 1.52s
2 0 2 -0.52 46.9 1.32s
3 0 3 -2.40 41.6 1.21s
4 0 4 -4.46 29.6 2.37s
5 0 5 -6.46 17.4 859ms
6 0 6 -8.91 4.0 433ms
7 1 1 -7.79 55.7 1.77s Restart
8 1 2 -8.84 5.7 434ms
72.7 1.71s Final orbitals
86.169771 seconds (101.21 M allocations: 80.243 GiB, 8.53% gc time, 7.77% compilation time: 100% of which was recompilation)These are the final phonon frequencies:
phret_q0.frequencies6-element Vector{Float64}:
-0.003498155362030899
-0.002977451160266179
-0.0029774511600920454
0.004302230615404216
0.004302230615706432
0.004353201747680393