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 -7.916402576079 -0.69 4.8 113ms
2 -7.921196023968 -2.32 -1.52 1.0 63.8ms
3 -7.921401835675 -3.69 -2.49 1.4 65.2ms
4 -7.921440886991 -4.41 -2.81 2.4 86.5ms
5 -7.921441537718 -6.19 -2.95 1.1 59.7ms
6 -7.921442007059 -6.33 -4.39 1.0 75.0ms
7 -7.921442021647 -7.84 -4.54 2.5 84.7ms
8 -7.921442022124 -9.32 -5.27 1.0 59.4ms
9 -7.921442022143 -10.74 -5.92 1.9 69.7ms
10 -7.921442022144 -11.87 -5.96 2.0 73.3ms
11 -7.921442022144 -12.54 -7.17 1.0 59.5ms
12 -7.921442022144 -13.91 -7.19 2.5 82.8ms
13 -7.921442022144 -15.05 -7.66 1.0 60.6ms
14 -7.921442022144 + -15.05 -9.51 1.0 60.7msNext 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 2.04s Non-interacting
1 0 1 0.31 52.6 3.78s
2 0 2 -0.52 47.2 1.33s
3 0 3 -2.40 41.9 1.23s
4 0 4 -4.46 30.0 1.02s
5 0 5 -6.46 17.6 718ms
6 0 6 -8.91 4.0 439ms
7 1 1 -7.86 55.6 1.91s Restart
8 1 2 -9.22 5.6 465ms
72.8 1.76s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.60s Non-interacting
1 0 1 0.31 52.6 1.54s
2 0 2 -0.52 47.2 1.34s
3 0 3 -2.40 41.9 1.25s
4 0 4 -4.46 30.0 985ms
5 0 5 -6.46 17.6 717ms
6 0 6 -8.91 4.0 424ms
7 1 1 -7.86 55.6 1.89s Restart
8 1 2 -9.22 5.6 467ms
72.8 1.79s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.64s Non-interacting
1 0 1 0.31 52.6 1.58s
2 0 2 -0.52 47.2 1.34s
3 0 3 -2.40 41.9 1.23s
4 0 4 -4.46 30.0 996ms
5 0 5 -6.46 17.6 715ms
6 0 6 -8.91 4.0 426ms
7 1 1 -7.86 55.6 1.87s Restart
8 1 2 -9.22 5.6 460ms
72.8 1.79s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.65s Non-interacting
1 0 1 0.31 52.6 2.90s
2 0 2 -0.52 47.2 1.39s
3 0 3 -2.40 41.9 1.19s
4 0 4 -4.46 30.0 962ms
5 0 5 -6.46 17.6 709ms
6 0 6 -8.91 4.0 434ms
7 1 1 -7.90 55.4 1.86s Restart
8 1 2 -9.27 5.5 460ms
72.8 1.75s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.60s Non-interacting
1 0 1 0.31 52.6 1.55s
2 0 2 -0.52 47.2 1.35s
3 0 3 -2.40 41.9 1.22s
4 0 4 -4.46 30.0 979ms
5 0 5 -6.46 17.6 712ms
6 0 6 -8.91 4.0 414ms
7 1 1 -7.90 55.4 1.83s Restart
8 1 2 -9.27 5.5 454ms
72.8 1.75s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.61s Non-interacting
1 0 1 0.31 52.6 1.54s
2 0 2 -0.52 47.2 1.38s
3 0 3 -2.40 41.9 1.25s
4 0 4 -4.46 30.0 964ms
5 0 5 -6.46 17.6 705ms
6 0 6 -8.91 4.0 428ms
7 1 1 -7.90 55.4 1.84s Restart
8 1 2 -9.27 5.5 451ms
72.8 1.76s Final orbitals
87.032570 seconds (101.48 M allocations: 80.478 GiB, 6.86% gc time, 8.61% compilation time: 100% of which was recompilation)These are the final phonon frequencies:
phret_q0.frequencies6-element Vector{Float64}:
-0.003498155358367355
-0.002977451159900199
-0.0029774511597451814
0.004302230631246928
0.004302230631581521
0.004353201760972836