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 -7.916429469819 -0.69 4.8 100ms
2 -7.921203360336 -2.32 -1.52 1.0 50.5ms
3 -7.921405499150 -3.69 -2.49 1.5 55.3ms
4 -7.921440893024 -4.45 -2.83 2.4 70.0ms
5 -7.921441610360 -6.14 -3.00 1.1 51.7ms
6 -7.921442004365 -6.40 -4.43 1.0 57.6ms
7 -7.921442021718 -7.76 -4.57 2.6 74.7ms
8 -7.921442022122 -9.39 -5.22 1.0 51.5ms
9 -7.921442022132 -11.02 -5.09 1.9 61.2ms
10 -7.921442022144 -10.93 -5.85 1.0 52.0ms
11 -7.921442022144 -12.23 -6.98 1.0 57.5ms
12 -7.921442022144 -13.34 -6.82 2.9 74.6ms
13 -7.921442022144 -14.35 -7.85 1.0 51.9ms
14 -7.921442022144 + -14.75 -8.00 1.9 60.6ms
15 -7.921442022144 -14.75 -8.79 1.0 57.9msNext 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 1.90s Non-interacting
1 0 1 0.31 52.3 2.20s
2 0 2 -0.52 46.9 1.46s
3 0 3 -2.40 41.7 1.35s
4 0 4 -4.46 29.7 1.02s
5 0 5 -6.46 17.5 727ms
6 0 6 -8.91 4.0 409ms
7 1 1 -7.84 55.6 1.97s Restart
8 1 2 -8.87 5.6 458ms
72.8 1.94s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
72.9 1.85s Non-interacting
1 0 1 0.31 52.3 1.65s
2 0 2 -0.52 46.9 1.46s
3 0 3 -2.40 41.7 1.33s
4 0 4 -4.46 29.7 1.04s
5 0 5 -6.46 17.5 733ms
6 0 6 -8.91 4.0 440ms
7 1 1 -7.84 55.6 2.02s Restart
8 1 2 -8.87 5.6 441ms
72.8 1.98s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.83s Non-interacting
1 0 1 0.31 52.3 2.37s
2 0 2 -0.52 46.9 1.41s
3 0 3 -2.40 41.7 1.42s
4 0 4 -4.46 29.7 1.06s
5 0 5 -6.46 17.5 732ms
6 0 6 -8.91 4.0 404ms
7 1 1 -7.84 55.6 1.98s Restart
8 1 2 -8.87 5.6 449ms
72.8 1.98s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.85s Non-interacting
1 0 1 0.31 52.3 1.68s
2 0 2 -0.52 46.9 1.47s
3 0 3 -2.40 41.7 1.33s
4 0 4 -4.46 29.6 1.05s
5 0 5 -6.46 17.5 735ms
6 0 6 -8.91 4.0 405ms
7 1 1 -7.83 55.6 2.00s Restart
8 1 2 -8.89 5.6 440ms
72.8 1.97s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.87s Non-interacting
1 0 1 0.31 52.3 1.71s
2 0 2 -0.52 46.9 1.45s
3 0 3 -2.40 41.7 2.02s
4 0 4 -4.46 29.6 1.00s
5 0 5 -6.46 17.5 734ms
6 0 6 -8.91 4.0 409ms
7 1 1 -7.83 55.6 2.01s Restart
8 1 2 -8.89 5.6 473ms
72.8 1.99s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.84s Non-interacting
1 0 1 0.31 52.3 1.71s
2 0 2 -0.52 46.9 1.47s
3 0 3 -2.40 41.7 1.38s
4 0 4 -4.46 29.6 1.06s
5 0 5 -6.46 17.5 749ms
6 0 6 -8.91 4.0 430ms
7 1 1 -7.83 55.6 2.01s Restart
8 1 2 -8.89 5.6 449ms
72.8 1.98s Final orbitals
87.570691 seconds (92.54 M allocations: 80.278 GiB, 7.19% gc time, 1.17% compilation time: 100% of which was recompilation)These are the final phonon frequencies:
phret_q0.frequencies6-element Vector{Float64}:
-0.0034981553571261934
-0.00297745115762518
-0.002977451157584445
0.00430223062962175
0.004302230629684215
0.004353201759944783