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 -7.916453895262 -0.69 4.6 157ms
2 -7.921210082539 -2.32 -1.52 1.0 57.3ms
3 -7.921403460094 -3.71 -2.49 1.2 59.4ms
4 -7.921440833972 -4.43 -2.81 2.8 81.6ms
5 -7.921441555468 -6.14 -2.96 1.1 59.6ms
6 -7.921442006479 -6.35 -4.50 1.0 58.2ms
7 -7.921442021555 -7.82 -4.47 2.9 87.8ms
8 -7.921442022114 -9.25 -5.12 1.0 154ms
9 -7.921442022137 -10.64 -5.25 1.4 61.9ms
10 -7.921442022143 -11.22 -5.87 1.0 58.3ms
11 -7.921442022144 -11.88 -6.11 1.5 65.0ms
12 -7.921442022144 -13.01 -6.36 1.1 59.6ms
13 -7.921442022144 -13.57 -7.01 1.0 58.2ms
14 -7.921442022144 -14.15 -7.44 1.5 798ms
15 -7.921442022144 + -Inf -8.07 1.6 120ms
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
---- ------- ------ ---------- ------- ------ ---------------
73.0 2.09s Non-interacting
1 0 1 0.31 52.5 9.34s
2 0 2 -0.52 47.0 1.47s
3 0 3 -2.40 41.6 1.27s
4 0 4 -4.46 29.6 1.01s
5 0 5 -6.46 17.4 743ms
6 0 6 -8.91 4.0 432ms
7 1 1 -7.77 56.2 2.05s Restart
8 1 2 -8.70 5.7 474ms
72.8 1.86s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
72.9 1.68s Non-interacting
1 0 1 0.31 52.5 1.58s
2 0 2 -0.52 47.0 1.39s
3 0 3 -2.40 41.6 1.27s
4 0 4 -4.46 29.6 1.77s
5 0 5 -6.46 17.4 682ms
6 0 6 -8.91 4.0 415ms
7 1 1 -7.77 56.2 1.90s Restart
8 1 2 -8.70 5.7 483ms
72.7 1.80s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
72.9 1.65s Non-interacting
1 0 1 0.31 52.5 1.57s
2 0 2 -0.52 47.0 1.37s
3 0 3 -2.40 41.6 1.24s
4 0 4 -4.46 29.6 980ms
5 0 5 -6.46 17.4 722ms
6 0 6 -8.91 4.0 432ms
7 1 1 -7.77 56.2 1.90s Restart
8 1 2 -8.70 5.7 457ms
72.7 1.81s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
72.9 1.66s Non-interacting
1 0 1 0.31 52.5 1.57s
2 0 2 -0.52 47.0 1.36s
3 0 3 -2.40 41.6 1.26s
4 0 4 -4.46 29.6 1.68s
5 0 5 -6.46 17.4 682ms
6 0 6 -8.90 4.0 414ms
7 1 1 -7.77 56.2 1.96s Restart
8 1 2 -8.70 5.7 482ms
72.7 1.85s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
72.9 1.68s Non-interacting
1 0 1 0.31 52.5 1.60s
2 0 2 -0.52 47.0 1.38s
3 0 3 -2.40 41.6 1.26s
4 0 4 -4.46 29.6 1.00s
5 0 5 -6.46 17.4 739ms
6 0 6 -8.90 4.0 436ms
7 1 1 -7.77 56.2 1.92s Restart
8 1 2 -8.70 5.7 460ms
72.8 1.78s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.62s Non-interacting
1 0 1 0.31 52.5 1.57s
2 0 2 -0.52 47.0 1.34s
3 0 3 -2.40 41.6 1.24s
4 0 4 -4.46 29.6 1.74s
5 0 5 -6.46 17.4 685ms
6 0 6 -8.90 4.0 420ms
7 1 1 -7.77 56.2 1.93s Restart
8 1 2 -8.70 5.7 474ms
72.8 1.83s Final orbitals
112.970271 seconds (151.11 M allocations: 82.676 GiB, 7.97% gc time, 26.95% compilation time)
These are the final phonon frequencies:
phret_q0.frequencies6-element Vector{Float64}:
-0.0034981553640066054
-0.0029774511675373454
-0.0029774511674652898
0.004302230628242684
0.004302230628598805
0.004353201757301661