This GPL software calculates phonon-phonon interactions via the third order force constants. It allows to obtain lattice thermal conductivity, phonon lifetime/linewidth, imaginary part of self energy at the lowest order, joint density of states (JDOS) and weighted-JDOS. For details see Phys. Rev. B 91, 094306 (2015) and

Available modules

$ ml av phono3py
$ ml phono3py

Example of Calculating Thermal Conductivity of Si Using VASP Code.

Calculating Force Constants

One needs to calculate second order and third order force constants using the diamond structure of silicon stored in POSCAR (the same form as in VASP) using single displacement calculations within supercell.

$ cat POSCAR
     5.4335600309153529    0.0000000000000000    0.0000000000000000
     0.0000000000000000    5.4335600309153529    0.0000000000000000
     0.0000000000000000    0.0000000000000000    5.4335600309153529
   0.8750000000000000 0.8750000000000000 0.8750000000000000
   0.8750000000000000 0.3750000000000000 0.3750000000000000
   0.3750000000000000 0.8750000000000000 0.3750000000000000
   0.3750000000000000 0.3750000000000000 0.8750000000000000
   0.1250000000000000 0.1250000000000000 0.1250000000000000
   0.1250000000000000 0.6250000000000000 0.6250000000000000
   0.6250000000000000 0.1250000000000000 0.6250000000000000
   0.6250000000000000 0.6250000000000000 0.1250000000000000

Generating Displacement Using 2 by 2 by 2 Supercell for Both Second and Third Order Force Constants

$ phono3py -d --dim="2 2 2" -c POSCAR

111 displacements is created stored in disp_fc3.yaml, and the structure input files with this displacements are POSCAR-00XXX, where the XXX=111.

disp_fc3.yaml POSCAR-00008 POSCAR-00017 POSCAR-00026 POSCAR-00035 POSCAR-00044 POSCAR-00053 POSCAR-00062 POSCAR-00071 POSCAR-00080 POSCAR-00089 POSCAR-00098 POSCAR-00107
POSCAR         POSCAR-00009 POSCAR-00018 POSCAR-00027 POSCAR-00036 POSCAR-00045 POSCAR-00054 POSCAR-00063 POSCAR-00072 POSCAR-00081 POSCAR-00090 POSCAR-00099 POSCAR-00108
POSCAR-00001   POSCAR-00010 POSCAR-00019 POSCAR-00028 POSCAR-00037 POSCAR-00046 POSCAR-00055 POSCAR-00064 POSCAR-00073 POSCAR-00082 POSCAR-00091 POSCAR-00100 POSCAR-00109
POSCAR-00002   POSCAR-00011 POSCAR-00020 POSCAR-00029 POSCAR-00038 POSCAR-00047 POSCAR-00056 POSCAR-00065 POSCAR-00074 POSCAR-00083 POSCAR-00092 POSCAR-00101 POSCAR-00110
POSCAR-00003   POSCAR-00012 POSCAR-00021 POSCAR-00030 POSCAR-00039 POSCAR-00048 POSCAR-00057 POSCAR-00066 POSCAR-00075 POSCAR-00084 POSCAR-00093 POSCAR-00102 POSCAR-00111
POSCAR-00004   POSCAR-00013 POSCAR-00022 POSCAR-00031 POSCAR-00040 POSCAR-00049 POSCAR-00058 POSCAR-00067 POSCAR-00076 POSCAR-00085 POSCAR-00094 POSCAR-00103
POSCAR-00005   POSCAR-00014 POSCAR-00023 POSCAR-00032 POSCAR-00041 POSCAR-00050 POSCAR-00059 POSCAR-00068 POSCAR-00077 POSCAR-00086 POSCAR-00095 POSCAR-00104
POSCAR-00006   POSCAR-00015 POSCAR-00024 POSCAR-00033 POSCAR-00042 POSCAR-00051 POSCAR-00060 POSCAR-00069 POSCAR-00078 POSCAR-00087 POSCAR-00096 POSCAR-00105
POSCAR-00007   POSCAR-00016 POSCAR-00025 POSCAR-00034 POSCAR-00043 POSCAR-00052 POSCAR-00061 POSCAR-00070 POSCAR-00079 POSCAR-00088 POSCAR-00097 POSCAR-00106

For each displacement the forces needs to be calculated, i.e. in form of the output file of VASP (vasprun.xml). For a single VASP calculations one needs KPOINTS, POTCAR, INCAR in your case directory (where you have POSCARS) and those 111 displacements calculations can be generated by script. Then each of the single 111 calculations is submitted by

disp-00001 disp-00009 disp-00017 disp-00025 disp-00033 disp-00041 disp-00049 disp-00057 disp-00065 disp-00073 disp-00081 disp-00089 disp-00097 disp-00105     INCAR
disp-00002 disp-00010 disp-00018 disp-00026 disp-00034 disp-00042 disp-00050 disp-00058 disp-00066 disp-00074 disp-00082 disp-00090 disp-00098 disp-00106     KPOINTS
disp-00003 disp-00011 disp-00019 disp-00027 disp-00035 disp-00043 disp-00051 disp-00059 disp-00067 disp-00075 disp-00083 disp-00091 disp-00099 disp-00107     POSCAR
disp-00004 disp-00012 disp-00020 disp-00028 disp-00036 disp-00044 disp-00052 disp-00060 disp-00068 disp-00076 disp-00084 disp-00092 disp-00100 disp-00108     POTCAR
disp-00005 disp-00013 disp-00021 disp-00029 disp-00037 disp-00045 disp-00053 disp-00061 disp-00069 disp-00077 disp-00085 disp-00093 disp-00101 disp-00109
disp-00006 disp-00014 disp-00022 disp-00030 disp-00038 disp-00046 disp-00054 disp-00062 disp-00070 disp-00078 disp-00086 disp-00094 disp-00102 disp-00110
disp-00007 disp-00015 disp-00023 disp-00031 disp-00039 disp-00047 disp-00055 disp-00063 disp-00071 disp-00079 disp-00087 disp-00095 disp-00103 disp-00111
disp-00008 disp-00016 disp-00024 disp-00032 disp-00040 disp-00048 disp-00056 disp-00064 disp-00072 disp-00080 disp-00088 disp-00096 disp-00104 disp_fc3.yaml

Taylor your script to fit into your project and other needs and submit all 111 calculations using script

$ ./

Collecting Results and Post-Processing With Phono3py

Once all jobs are finished and vasprun.xml is created in each disp-XXXXX directory the collection is done by

$ phono3py --cf3 disp-{00001..00111}/vasprun.xml

and disp_fc2.yaml, FORCES_FC2, FORCES_FC3 and disp_fc3.yaml should appear and put into the hdf format by

$ phono3py --dim="2 2 2" -c POSCAR

resulting in fc2.hdf5 and fc3.hdf5

Thermal Conductivity

The phonon lifetime calculations takes some time, however is independent on grid points, so could be splitted:

$ phono3py --fc3 --fc2 --dim="2 2 2" --mesh="9 9 9" --sigma 0.1 --wgp

Inspecting ir_grid_points.yaml

$ grep grid_point ir_grid_points.yaml
num_reduced_ir_grid_points: 35
ir_grid_points:  # [address, weight]
* grid_point: 0
* grid_point: 1
* grid_point: 2
* grid_point: 3
* grid_point: 4
* grid_point: 10
* grid_point: 11
* grid_point: 12
* grid_point: 13
* grid_point: 20
* grid_point: 21
* grid_point: 22
* grid_point: 30
* grid_point: 31
* grid_point: 40
* grid_point: 91
* grid_point: 92
* grid_point: 93
* grid_point: 94
* grid_point: 101
* grid_point: 102
* grid_point: 103
* grid_point: 111
* grid_point: 112
* grid_point: 121
* grid_point: 182
* grid_point: 183
* grid_point: 184
* grid_point: 192
* grid_point: 193
* grid_point: 202
* grid_point: 273
* grid_point: 274
* grid_point: 283
* grid_point: 364

one finds which grid points needed to be calculated, for instance using following

$ phono3py --fc3 --fc2 --dim="2 2 2" --mesh="9 9 9" -c POSCAR  --sigma 0.1 --br --write-gamma --gp="0 1 2

one calculates grid points 0, 1, 2. To automize one can use for instance scripts to submit 5 points in series, see

$ qsub

Finally the thermal conductivity result is produced by grouping single conductivity per grid calculations using

$ phono3py --fc3 --fc2 --dim="2 2 2" --mesh="9 9 9" --br --read_gamma