Phonon computations

This is a quick sketch how to run a simple phonon calculation using DFTK. 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   -7.916453171422                   -0.69    4.8    102ms
  2   -7.921212118254       -2.32       -1.52    1.0   52.0ms
  3   -7.921408092952       -3.71       -2.49    1.4   56.8ms
  4   -7.921441008129       -4.48       -2.84    2.5   70.5ms
  5   -7.921441694018       -6.16       -3.06    1.2   62.2ms
  6   -7.921442007194       -6.50       -4.58    1.0   53.0ms
  7   -7.921442021864       -7.83       -4.64    3.1   81.9ms
  8   -7.921442022130       -9.58       -5.29    1.0   52.9ms
  9   -7.921442022143      -10.90       -5.81    1.5   58.7ms
 10   -7.921442022144      -11.88       -6.05    1.5   65.0ms
 11   -7.921442022144      -12.73       -6.62    1.1   56.8ms
 12   -7.921442022144      -13.57       -8.07    1.8   62.7ms

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]);

Iter  Restart  Krydim  log10(res)  avg(CG)  Δtime   Comment
----  -------  ------  ----------  -------  ------  ---------------
                                      73.1   1.93s  Non-interacting
   1        0       1        0.31     52.5   2.18s
   2        0       2       -0.52     47.1   1.44s
   3        0       3       -2.40     41.8   1.32s
   4        0       4       -4.46     30.0   1.03s
   5        0       5       -6.46     17.5   725ms
   6        0       6       -8.91      4.0   407ms
   7        1       1       -7.86     55.6   1.95s  Restart
   8        1       2       -9.07      5.6   443ms
                                      72.8   1.93s  Final orbitals
Iter  Restart  Krydim  log10(res)  avg(CG)  Δtime   Comment
----  -------  ------  ----------  -------  ------  ---------------
                                      73.0   1.80s  Non-interacting
   1        0       1        0.31     52.5   1.67s
   2        0       2       -0.52     47.1   1.44s
   3        0       3       -2.40     41.8   1.96s
   4        0       4       -4.46     30.0   1.01s
   5        0       5       -6.46     17.5   733ms
   6        0       6       -8.91      4.0   411ms
   7        1       1       -7.86     55.6   1.97s  Restart
   8        1       2       -9.07      5.6   451ms
                                      72.9   1.96s  Final orbitals
Iter  Restart  Krydim  log10(res)  avg(CG)  Δtime   Comment
----  -------  ------  ----------  -------  ------  ---------------
                                      73.0   1.81s  Non-interacting
   1        0       1        0.31     52.5   1.67s
   2        0       2       -0.52     47.1   1.45s
   3        0       3       -2.40     41.8   1.33s
   4        0       4       -4.46     30.0   1.03s
   5        0       5       -6.46     17.5   734ms
   6        0       6       -8.91      4.0   407ms
   7        1       1       -7.86     55.6   1.98s  Restart
   8        1       2       -9.07      5.6   442ms
                                      72.8   1.94s  Final orbitals
Iter  Restart  Krydim  log10(res)  avg(CG)  Δtime   Comment
----  -------  ------  ----------  -------  ------  ---------------
                                      73.1   1.79s  Non-interacting
   1        0       1        0.31     52.5   1.66s
   2        0       2       -0.52     47.1   1.44s
   3        0       3       -2.40     41.8   1.30s
   4        0       4       -4.46     30.0   1.69s
   5        0       5       -6.46     17.5   695ms
   6        0       6       -8.91      4.0   404ms
   7        1       1       -7.88     55.3   1.95s  Restart
   8        1       2       -9.14      5.4   442ms
                                      72.8   1.96s  Final orbitals
Iter  Restart  Krydim  log10(res)  avg(CG)  Δtime   Comment
----  -------  ------  ----------  -------  ------  ---------------
                                      73.0   1.80s  Non-interacting
   1        0       1        0.31     52.5   1.68s
   2        0       2       -0.52     47.1   1.44s
   3        0       3       -2.40     41.8   1.32s
   4        0       4       -4.46     30.0   1.04s
   5        0       5       -6.46     17.5   731ms
   6        0       6       -8.91      4.0   416ms
   7        1       1       -7.88     55.3   1.95s  Restart
   8        1       2       -9.14      5.4   446ms
                                      72.8   1.95s  Final orbitals
Iter  Restart  Krydim  log10(res)  avg(CG)  Δtime   Comment
----  -------  ------  ----------  -------  ------  ---------------
                                      73.0   1.81s  Non-interacting
   1        0       1        0.31     52.5   1.67s
   2        0       2       -0.52     47.1   1.45s
   3        0       3       -2.40     41.8   1.32s
   4        0       4       -4.46     30.0   1.03s
   5        0       5       -6.46     17.5   733ms
   6        0       6       -8.91      4.0   1.10s
   7        1       1       -7.88     55.3   1.88s  Restart
   8        1       2       -9.14      5.4   441ms
                                      72.8   1.96s  Final orbitals
 86.322377 seconds (94.39 M allocations: 80.433 GiB, 7.33% gc time, 1.17% compilation time: 100% of which was recompilation)

These are the final phonon frequencies:

phret_q0.frequencies

6-element Vector{Float64}:
 -0.0034981553780456666
 -0.0029774511810992123
 -0.0029774511780980843
  0.004302230587303587
  0.004302230591275319
  0.00435320172395886