Output files

Additional four files generated by the calculation are explained below. They have different extension names. '.mmn' file is for storing the overlap matrix elements $M_{mn}^{({\rm {\bf k}},{\rm {\bf b}})}$. '.amn' is for the initial guess projection matrix element $A_{mn}^{({\rm {\bf k}})}$. '.eigen' is for the eigenenergies and eigenstates at each k point. The '.HWR' file is for the hopping integrals among MLWFs on a set of lattice vectors which lies in the Wigner-Seitz supercells conjugated with the sampled k grids. For restarting optimization calculation, '.mmn' file will be read instead of written. More detailed information of the four files will be given below.

A. File format of '.mmn' file
This file structure is closely following that in Wannier90 [82]. The first line of this file is the description of the numbers in the second line. The numbers from left to right in the second line are the number ($N_{win}$) of included bands within the outer window, the number of k points, the number of b vectors, the number of spin component, respectively. The next lines are data blocks of $M_{mn}^{({\rm {\bf k}},{\rm {\bf b}})}$. The most outer loop is for spin component. The next is the loop of k points and then b vectors. The most inner loops are the band index $n$ and $m$, respectively. In each block, the first line are 5 numbers. The first two numbers are the index of present k point and the index of neighboring point k+b, respectively. The next three numbers indicates in which unit cell k+b point lies. From the second line are the real and imaginary part of each matrix element. In each block, there are $N_{win} \times N_{win}$ complex numbers. An example file, generated by the input file 'Si.dat', is shown here:

Mmn_zero(k,b). band_num, kpt_num, bvector num, spinsize
           10          512            8            1
    1  512    0    0    0
    0.571090282808   -0.819911068319
    0.000031357498   -0.000045367307
   -0.000149292597    0.000215591228
   -0.003821911756    0.005522040495
    0.028616452988    0.019804944108
    0.003677357735    0.002544970842
   -0.006610037555   -0.004574771451
   -0.000950861169   -0.000658076633
   -0.000000008855    0.000000005272
    ........
    .....
    ...
    .

B. File format of '.amn' file
This file structure is closely following that in Wannier90 [82]. The first line of the file is the description of the whole file. Obviously, the four numbers in the second line are the number ($N_{win}$) of bands within the outer window, the number of k points, the number of target MLWFs and the number of spin component, respectively. Similarly, the data blocks are written in loops. The most outer loop is spin component and then k points, target MLWFs and number of bands. As described in the first line of this file. In each block, the first three integers are the band index, the index of MLWFs and index of k points, respectively. The next are real and imaginary of that matrix element. An example file, generated by the input file 'Si.dat', is shown here:

Amn. Fist line BANDNUM, KPTNUM, WANNUM, spinsize. Next is m n k and elements.Spin is the most outer loop.
           10          512            8            1
    1    1    1    0.053943539299    0.000161703961
    2    1    1   -0.000525446164   -0.000000008885
    3    1    1    0.002498021589    0.000000084311
    ... ...
    ... ...
   10    1    1   -0.000000023582   -0.000000000069
    1    2    1    0.053943534952    0.000161703965
    2    2    1    0.033382665372    0.000000493665
    3    2    1   -0.051189536188   -0.000001480360
    ........
    .....
    ...
    .

C. File format of '.eigen' file
This file contains the eigenenergies and eigenstates at each k point. The first line is the Fermi level of system. The number of bands is indicated in the second line of the file. The next data are mainly in two parts. The first part is the eigenenergies and the second one is the corresponding eigenstates. In each part, the loop of spin component is the most outer one. The next loop is k points, followed by band index. For eigenstates, there is one more inner loop for the basis set. An example file, generated by the input file 'Si.dat', is shown here:

Fermi level -0.112747
Number of bands 10
    1    1   -0.566228100179
    2    1   -0.122518136808
    3    1   -0.122518129040
    4    1   -0.122518115949
    5    1   -0.026598417854
    ... ...
    ... ...
WF kpt 1 (0.00000000,0.00000000,0.00000000)
1 1   0.4790338281  -0.0014359768
1 2   0.0440709749  -0.0001321095
1 3  -0.0000003333  -0.0000000000
    ........
    .....
    ...
    .

D. File format of '.HWR' file
This file contains the hopping integrals between the $m$th MLWF, $\vert m,{\bf0}\rangle$, in the home unit cell and the $n$th MLWF, $\vert n, {\bf R}\rangle$, in the unit cell at R. The matrix element $\langle m,{\bf0} \vert {\hat H} \vert n,{\bf R}\rangle$ is written in the following way. In '.HWR' file, the first line is just a description. The number of MLWFs, number of lattice vectors inside of Wigner-Seitz supercell are in the second and third line, respectively. The unit cell vectors are given in the fifth, sixth and seventh lines. Spin polarization, whether it is a non-spin polarized calculation or a spin polarized one with collinear or noncollinear magnetic configuration, is given in the eighth line. The ninth line gives the Fermi level. From the tenth line, the block data starts. The outer most loop is spin component. The next loop is for R and the last two are loops of $m$ and $n$, respectively. Each R is written at the first line of each block together with its degeneracy. The index of $m$ and $n$ is printed and followed by the real and imaginary parts of hopping integrals in each line. An example file, generated by the input file 'Si.dat', is shown here:

Real-space Hamiltonian in Wannier Gauge on Wigner-Seitz supercell.
Number of Wannier Function 8
Number of Wigner-Seitz supercell 617
Lattice vector (in Bohr)
   5.10000    0.00000    5.10000
   0.00000    5.10000    5.10000
   5.10000    5.10000    0.00000
collinear calculation spinsize 1
Fermi level -0.112747
R (   -6    2    2 )    4
   1     1     -0.000078903162   -0.000000003750
   1     2      0.000024237763   -0.000000000148
   1     3      0.000024237691   -0.000000000341
   1     4      0.000024238375    0.000000004117
   1     5      0.000072656918   -0.000000000196
   1     6     -0.000022470544   -0.000000000859
   1     7     -0.000022481557    0.000000000750
   1     8     -0.000022492706    0.000000000148
   2     1      0.000024238091    0.000000000049
   2     2     -0.000078901874   -0.000000000011
   2     3      0.000024234912   -0.000000000023
    ........
    .....
    ...
    .