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 -7.916437099022 -0.69 4.5 102ms
2 -7.921209419540 -2.32 -1.52 1.0 57.8ms
3 -7.921405232816 -3.71 -2.49 1.4 62.5ms
4 -7.921440943449 -4.45 -2.82 2.6 84.3ms
5 -7.921441628238 -6.16 -3.00 1.1 53.4ms
6 -7.921442006616 -6.42 -4.52 1.0 52.6ms
7 -7.921442021705 -7.82 -4.53 2.9 78.3ms
8 -7.921442022119 -9.38 -5.16 1.0 52.7ms
9 -7.921442022140 -10.69 -5.42 1.2 55.2ms
10 -7.921442022143 -11.48 -5.81 1.2 55.1ms
11 -7.921442022144 -12.03 -6.42 1.1 54.9ms
12 -7.921442022144 -13.04 -7.09 2.0 63.9ms
13 -7.921442022144 -14.45 -7.35 1.9 63.9ms
14 -7.921442022144 -15.05 -7.97 1.2 58.3ms
15 -7.921442022144 + -15.05 -8.66 1.9 63.9msNext 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 1.94s Non-interacting
1 0 1 0.31 52.3 2.21s
2 0 2 -0.52 47.0 1.47s
3 0 3 -2.40 41.7 1.33s
4 0 4 -4.46 29.6 1.03s
5 0 5 -6.46 17.4 740ms
6 0 6 -8.91 4.0 425ms
7 1 1 -7.80 55.8 1.98s Restart
8 1 2 -8.81 5.7 456ms
72.8 1.98s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
72.9 1.83s Non-interacting
1 0 1 0.31 52.3 1.68s
2 0 2 -0.52 47.0 1.47s
3 0 3 -2.40 41.7 1.33s
4 0 4 -4.46 29.6 1.04s
5 0 5 -6.46 17.4 747ms
6 0 6 -8.91 4.0 468ms
7 1 1 -7.80 55.8 2.66s Restart
8 1 2 -8.81 5.7 444ms
72.7 1.99s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.85s Non-interacting
1 0 1 0.31 52.3 1.72s
2 0 2 -0.52 47.0 1.51s
3 0 3 -2.40 41.7 1.36s
4 0 4 -4.46 29.6 1.05s
5 0 5 -6.46 17.4 759ms
6 0 6 -8.91 4.0 441ms
7 1 1 -7.80 55.8 2.02s Restart
8 1 2 -8.81 5.7 469ms
72.8 2.02s 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 47.0 1.48s
3 0 3 -2.40 41.7 1.35s
4 0 4 -4.46 29.6 1.04s
5 0 5 -6.46 17.4 759ms
6 0 6 -8.91 4.0 434ms
7 1 1 -7.81 55.6 2.00s Restart
8 1 2 -8.86 5.7 456ms
72.7 2.61s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.84s Non-interacting
1 0 1 0.31 52.3 1.69s
2 0 2 -0.52 47.0 1.47s
3 0 3 -2.40 41.7 1.33s
4 0 4 -4.46 29.6 1.04s
5 0 5 -6.46 17.4 755ms
6 0 6 -8.91 4.0 417ms
7 1 1 -7.81 55.6 1.99s Restart
8 1 2 -8.86 5.7 458ms
72.8 2.00s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.84s Non-interacting
1 0 1 0.31 52.3 1.70s
2 0 2 -0.52 47.0 1.47s
3 0 3 -2.40 41.7 1.35s
4 0 4 -4.46 29.6 1.03s
5 0 5 -6.46 17.4 736ms
6 0 6 -8.91 4.0 411ms
7 1 1 -7.81 55.6 2.00s Restart
8 1 2 -8.86 5.7 454ms
72.8 1.95s Final orbitals
87.863349 seconds (92.44 M allocations: 79.929 GiB, 7.18% gc time, 1.18% compilation time: 100% of which was recompilation)These are the final phonon frequencies:
phret_q0.frequencies6-element Vector{Float64}:
-0.0034981553547732895
-0.002977451156053137
-0.002977451155832413
0.004302230635489251
0.00430223063565305
0.0043532017650495395