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 -7.916455961710 -0.69 4.8 114ms
2 -7.921209780229 -2.32 -1.52 1.0 55.7ms
3 -7.921405800210 -3.71 -2.49 1.2 59.5ms
4 -7.921440934485 -4.45 -2.82 2.4 77.5ms
5 -7.921441637524 -6.15 -3.01 1.1 69.5ms
6 -7.921442007786 -6.43 -4.54 1.0 57.6ms
7 -7.921442021588 -7.86 -4.49 2.8 85.0ms
8 -7.921442022121 -9.27 -5.25 1.0 58.3ms
9 -7.921442022142 -10.67 -5.57 1.5 63.8ms
10 -7.921442022144 -11.79 -6.01 1.4 62.4ms
11 -7.921442022144 -12.31 -6.49 1.0 58.3ms
12 -7.921442022144 -13.24 -6.97 1.8 78.1ms
13 -7.921442022144 -14.45 -7.45 1.5 66.2ms
14 -7.921442022144 -15.05 -8.15 1.1 62.2msNext 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 2.02s Non-interacting
1 0 1 0.31 52.5 4.94s
2 0 2 -0.52 47.0 1.28s
3 0 3 -2.40 41.7 1.22s
4 0 4 -4.46 29.6 980ms
5 0 5 -6.46 17.5 718ms
6 0 6 -8.91 4.0 425ms
7 1 1 -7.83 55.6 1.91s Restart
8 1 2 -8.88 5.6 475ms
72.8 1.77s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.61s 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 41.7 1.24s
4 0 4 -4.46 29.6 963ms
5 0 5 -6.46 17.5 735ms
6 0 6 -8.91 4.0 428ms
7 1 1 -7.83 55.6 1.87s Restart
8 1 2 -8.88 5.6 466ms
72.7 1.76s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
72.9 1.59s Non-interacting
1 0 1 0.31 52.5 1.56s
2 0 2 -0.52 47.0 1.33s
3 0 3 -2.40 41.7 1.26s
4 0 4 -4.46 29.6 982ms
5 0 5 -6.46 17.5 730ms
6 0 6 -8.91 4.0 417ms
7 1 1 -7.83 55.6 1.85s Restart
8 1 2 -8.88 5.6 465ms
72.7 1.75s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.60s Non-interacting
1 0 1 0.31 52.5 1.54s
2 0 2 -0.52 47.0 1.33s
3 0 3 -2.40 41.7 1.20s
4 0 4 -4.46 29.6 956ms
5 0 5 -6.46 17.5 693ms
6 0 6 -8.91 4.0 436ms
7 1 1 -7.83 55.6 1.95s Restart
8 1 2 -8.87 5.6 1.64s
72.7 1.84s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
72.9 1.57s Non-interacting
1 0 1 0.31 52.5 1.53s
2 0 2 -0.52 47.0 1.33s
3 0 3 -2.40 41.7 1.22s
4 0 4 -4.46 29.6 969ms
5 0 5 -6.46 17.5 715ms
6 0 6 -8.91 4.0 423ms
7 1 1 -7.83 55.6 1.84s Restart
8 1 2 -8.87 5.6 464ms
72.7 1.75s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
72.9 1.60s Non-interacting
1 0 1 0.31 52.5 1.56s
2 0 2 -0.52 47.0 1.34s
3 0 3 -2.40 41.7 1.24s
4 0 4 -4.46 29.6 971ms
5 0 5 -6.46 17.5 730ms
6 0 6 -8.91 4.0 425ms
7 1 1 -7.83 55.6 1.87s Restart
8 1 2 -8.87 5.6 475ms
72.7 1.79s Final orbitals
87.154399 seconds (100.36 M allocations: 80.248 GiB, 8.45% gc time, 7.58% compilation time: 100% of which was recompilation)These are the final phonon frequencies:
phret_q0.frequencies6-element Vector{Float64}:
-0.0034981553608677595
-0.0029774511605626165
-0.0029774511603546942
0.004302230616223761
0.004302230617405771
0.004353201748920974