The basis.in input file
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This file is used to define the unit cell for phonon calculations.
- The format of this file must be as follows:
N_basis id(0) mass(0) id(1) mass(1) ... id(N_basis-1) mass(N_basis-1) map(1) map(2) ... map(N)
N_basisis the number of atoms in the unit cell you choose. For example, it can be 2 for diamond silicon if you use the primitive cell as the unit cell.
- The next
N_basislines contain the atom indices (using the order as in the xyz.in file; starting from 0) and masses for the basis atoms. For the example of diamond silicon,
mass(0)=28are the index and mass for the first basis atom, and
mass(0)=28are the index and mass for the second basis atom.
- The remaining lines map the atoms in the xyz.in file to the basis atoms. If the
n-th atom in the xyz.in file is equivalent to (under translation) the
m-th basis atom in the unit cell, we have
map(n)=m. In our example,
map(n)is either 0 (equivalent to the first basis atom) or 1 (equivalent to the second basis atom).
- See the tutorial on phonon dispersion for an explicit example.