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 -7.916350006263 -0.69 4.9 119ms
2 -7.921204959321 -2.31 -1.52 1.0 54.2ms
3 -7.921408251064 -3.69 -2.49 1.5 59.8ms
4 -7.921440990160 -4.48 -2.85 2.5 74.2ms
5 -7.921441733877 -6.13 -3.10 1.1 55.5ms
6 -7.921442009725 -6.56 -4.52 1.1 55.8ms
7 -7.921442021923 -7.91 -4.70 3.0 83.8ms
8 -7.921442022133 -9.68 -5.36 1.0 64.6ms
9 -7.921442022142 -11.05 -5.48 1.6 62.4ms
10 -7.921442022144 -11.65 -6.14 1.0 55.3ms
11 -7.921442022144 -12.75 -7.16 1.4 59.8ms
12 -7.921442022144 -13.71 -7.56 2.8 77.9ms
13 -7.921442022144 + -Inf -8.56 1.4 60.5msNext 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
---- ------- ------ ---------- ------- ------ ---------------
73.1 1.94s Non-interacting
1 0 1 0.31 52.7 3.58s
2 0 2 -0.52 47.2 1.31s
3 0 3 -2.40 41.9 1.19s
4 0 4 -4.46 29.9 936ms
5 0 5 -6.46 17.6 708ms
6 0 6 -8.91 4.0 411ms
7 1 1 -7.84 55.7 1.84s Restart
8 1 2 -9.13 5.6 1.66s
72.9 1.90s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.1 1.53s Non-interacting
1 0 1 0.31 52.7 1.49s
2 0 2 -0.52 47.2 1.31s
3 0 3 -2.40 41.9 1.18s
4 0 4 -4.46 29.9 944ms
5 0 5 -6.46 17.6 689ms
6 0 6 -8.91 4.0 415ms
7 1 1 -7.84 55.7 1.80s Restart
8 1 2 -9.13 5.6 452ms
72.9 1.72s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.57s Non-interacting
1 0 1 0.31 52.7 1.51s
2 0 2 -0.52 47.2 1.32s
3 0 3 -2.40 41.9 1.20s
4 0 4 -4.46 29.9 946ms
5 0 5 -6.46 17.6 699ms
6 0 6 -8.91 4.0 412ms
7 1 1 -7.84 55.7 1.82s Restart
8 1 2 -9.13 5.6 439ms
72.8 1.71s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.1 1.56s Non-interacting
1 0 1 0.31 52.7 1.60s
2 0 2 -0.52 47.2 1.30s
3 0 3 -2.40 41.9 1.19s
4 0 4 -4.46 29.9 941ms
5 0 5 -6.46 17.6 703ms
6 0 6 -8.91 4.0 414ms
7 1 1 -7.84 55.8 1.82s Restart
8 1 2 -9.06 5.6 448ms
72.9 1.73s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.56s Non-interacting
1 0 1 0.31 52.7 1.51s
2 0 2 -0.52 47.2 1.30s
3 0 3 -2.40 41.9 1.18s
4 0 4 -4.46 29.9 944ms
5 0 5 -6.46 17.6 1.99s
6 0 6 -8.91 4.0 427ms
7 1 1 -7.84 55.8 1.94s Restart
8 1 2 -9.06 5.6 438ms
72.9 1.71s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.57s Non-interacting
1 0 1 0.31 52.7 1.53s
2 0 2 -0.52 47.2 1.32s
3 0 3 -2.40 41.9 1.21s
4 0 4 -4.46 29.9 955ms
5 0 5 -6.46 17.6 711ms
6 0 6 -8.91 4.0 410ms
7 1 1 -7.84 55.8 1.85s Restart
8 1 2 -9.06 5.6 451ms
72.9 1.74s Final orbitals
85.325979 seconds (100.55 M allocations: 80.481 GiB, 7.86% gc time, 7.52% compilation time: 100% of which was recompilation)These are the final phonon frequencies:
phret_q0.frequencies6-element Vector{Float64}:
-0.003498155352273254
-0.0029774511535356676
-0.0029774511530048977
0.0043022306366989884
0.00430223063730323
0.004353201767283339