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 -7.916466529626 -0.69 4.9 114ms
2 -7.921211961042 -2.32 -1.52 1.0 56.5ms
3 -7.921407357331 -3.71 -2.49 1.4 72.3ms
4 -7.921441045493 -4.47 -2.83 2.6 80.8ms
5 -7.921441690942 -6.19 -3.04 1.1 58.8ms
6 -7.921442010310 -6.50 -4.57 1.0 56.8ms
7 -7.921442021824 -7.94 -4.61 2.9 88.3ms
8 -7.921442022125 -9.52 -5.27 1.0 58.0ms
9 -7.921442022142 -10.77 -5.53 1.5 76.2ms
10 -7.921442022144 -11.67 -6.17 1.4 62.8ms
11 -7.921442022144 -12.47 -6.55 1.5 62.9ms
12 -7.921442022144 -13.59 -6.94 1.4 59.8ms
13 -7.921442022144 -14.15 -7.33 1.9 66.7ms
14 -7.921442022144 -14.75 -7.97 1.5 63.9ms
15 -7.921442022144 + -14.75 -9.01 1.8 75.9msNext 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 2.34s Non-interacting
1 0 1 0.31 52.4 3.88s
2 0 2 -0.52 47.0 1.55s
3 0 3 -2.40 41.7 1.38s
4 0 4 -4.46 29.7 2.40s
5 0 5 -6.46 17.4 743ms
6 0 6 -8.91 4.0 530ms
7 1 1 -7.79 55.9 2.06s Restart
8 1 2 -8.79 5.7 472ms
72.8 2.07s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.92s Non-interacting
1 0 1 0.31 52.4 1.77s
2 0 2 -0.52 47.0 1.54s
3 0 3 -2.40 41.7 1.38s
4 0 4 -4.46 29.7 1.09s
5 0 5 -6.46 17.4 779ms
6 0 6 -8.91 4.0 432ms
7 1 1 -7.79 55.9 2.07s Restart
8 1 2 -8.79 5.7 461ms
72.8 2.03s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.91s Non-interacting
1 0 1 0.31 52.4 1.75s
2 0 2 -0.52 47.0 1.51s
3 0 3 -2.40 41.7 1.37s
4 0 4 -4.46 29.7 1.08s
5 0 5 -6.46 17.4 768ms
6 0 6 -8.91 4.0 417ms
7 1 1 -7.79 55.9 2.08s Restart
8 1 2 -8.79 5.7 467ms
72.8 2.06s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.92s Non-interacting
1 0 1 0.31 52.4 1.76s
2 0 2 -0.52 47.0 1.52s
3 0 3 -2.40 41.7 1.39s
4 0 4 -4.46 29.7 1.07s
5 0 5 -6.46 17.4 762ms
6 0 6 -8.91 4.0 414ms
7 1 1 -7.79 55.9 2.07s Restart
8 1 2 -8.79 5.7 464ms
72.7 3.67s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.89s Non-interacting
1 0 1 0.31 52.4 1.77s
2 0 2 -0.52 47.0 1.54s
3 0 3 -2.40 41.7 1.40s
4 0 4 -4.46 29.7 1.10s
5 0 5 -6.46 17.4 777ms
6 0 6 -8.91 4.0 431ms
7 1 1 -7.79 55.9 2.08s Restart
8 1 2 -8.79 5.7 476ms
72.8 2.05s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.92s Non-interacting
1 0 1 0.31 52.4 1.76s
2 0 2 -0.52 47.0 1.53s
3 0 3 -2.40 41.7 1.38s
4 0 4 -4.46 29.7 1.09s
5 0 5 -6.46 17.4 775ms
6 0 6 -8.91 4.0 431ms
7 1 1 -7.79 55.9 2.08s Restart
8 1 2 -8.79 5.7 479ms
72.8 2.06s Final orbitals
97.427161 seconds (101.39 M allocations: 80.348 GiB, 7.55% gc time, 7.34% compilation time: 100% of which was recompilation)These are the final phonon frequencies:
phret_q0.frequencies6-element Vector{Float64}:
-0.0034981553545630185
-0.0029774511563761966
-0.002977451156077501
0.004302230636694282
0.004302230636942272
0.004353201765856324