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 -7.916429695588 -0.69 4.8 174ms
2 -7.921209261904 -2.32 -1.52 1.0 60.9ms
3 -7.921405376871 -3.71 -2.49 1.4 67.0ms
4 -7.921440910007 -4.45 -2.82 2.6 87.5ms
5 -7.921441626003 -6.15 -3.00 1.1 76.3ms
6 -7.921442006231 -6.42 -4.56 1.0 84.1ms
7 -7.921442021672 -7.81 -4.52 3.0 122ms
8 -7.921442022123 -9.35 -5.25 1.0 61.3ms
9 -7.921442022143 -10.69 -5.91 1.8 70.0ms
10 -7.921442022144 -12.24 -6.01 1.9 73.1ms
11 -7.921442022144 -12.53 -6.49 1.0 61.3ms
12 -7.921442022144 -13.62 -6.94 1.2 63.7ms
13 -7.921442022144 + -Inf -7.41 1.1 64.1ms
14 -7.921442022144 -15.05 -7.77 1.2 136ms
15 -7.921442022144 -15.05 -9.64 1.1 62.4ms
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
---- ------- ------ ---------- ------- ------ ---------------
72.9 2.14s Non-interacting
1 0 1 0.31 52.2 9.76s
2 0 2 -0.52 46.9 1.45s
3 0 3 -2.40 41.5 1.28s
4 0 4 -4.46 29.5 1.03s
5 0 5 -6.46 17.3 742ms
6 0 6 -8.91 4.0 445ms
7 1 1 -7.84 55.3 2.10s Restart
8 1 2 -8.88 5.5 498ms
72.6 1.87s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
72.8 1.69s Non-interacting
1 0 1 0.31 52.2 1.66s
2 0 2 -0.52 46.9 1.38s
3 0 3 -2.40 41.5 1.29s
4 0 4 -4.46 29.5 1.00s
5 0 5 -6.46 17.3 742ms
6 0 6 -8.91 4.0 432ms
7 1 1 -7.84 55.3 2.64s Restart
8 1 2 -8.88 5.5 449ms
72.7 1.85s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
72.9 1.69s Non-interacting
1 0 1 0.31 52.2 1.62s
2 0 2 -0.52 46.9 1.40s
3 0 3 -2.40 41.5 1.29s
4 0 4 -4.46 29.5 1.02s
5 0 5 -6.46 17.3 744ms
6 0 6 -8.91 4.0 438ms
7 1 1 -7.84 55.3 1.90s Restart
8 1 2 -8.88 5.5 466ms
72.7 1.80s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
72.8 1.67s Non-interacting
1 0 1 0.31 52.2 1.57s
2 0 2 -0.52 46.9 2.11s
3 0 3 -2.40 41.5 1.17s
4 0 4 -4.46 29.5 1.01s
5 0 5 -6.46 17.4 739ms
6 0 6 -8.91 4.0 441ms
7 1 1 -7.84 55.3 1.95s Restart
8 1 2 -8.89 5.5 481ms
72.6 1.88s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
72.8 1.73s Non-interacting
1 0 1 0.31 52.2 1.63s
2 0 2 -0.52 46.9 1.38s
3 0 3 -2.40 41.5 1.26s
4 0 4 -4.46 29.5 1.00s
5 0 5 -6.46 17.4 721ms
6 0 6 -8.91 4.0 431ms
7 1 1 -7.84 55.3 1.93s Restart
8 1 2 -8.89 5.5 479ms
72.7 2.63s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
72.9 1.60s Non-interacting
1 0 1 0.31 52.2 1.63s
2 0 2 -0.52 46.9 1.42s
3 0 3 -2.40 41.5 1.28s
4 0 4 -4.46 29.5 1.02s
5 0 5 -6.46 17.4 752ms
6 0 6 -8.91 4.0 460ms
7 1 1 -7.84 55.3 1.94s Restart
8 1 2 -8.89 5.5 470ms
72.7 1.87s Final orbitals
116.651988 seconds (151.00 M allocations: 82.492 GiB, 8.87% gc time, 26.91% compilation time)
These are the final phonon frequencies:
phret_q0.frequencies6-element Vector{Float64}:
-0.0034981553559870022
-0.002977451157259467
-0.0029774511568421294
0.004302230631526972
0.004302230631806558
0.004353201761813051