# nextnano.NEGF - Software for Quantum Transport

### nextnanomat

Software documentation

### nextnano++

Software documentation

Examples

### nextnano GmbH

qcl:material_database

## Material database

The default material parameters are stored in a database file called Material_Database.xml.

This default material database can be open in the nextnanomat GUI though:

File ⇒ Open nextnano.NEGF Default Database

If you run nextnano.NEGF via the nextnanomat GUI, you can choose to read in a customized material database as follows:

nextnanomat ⇒ Tools ⇒ Options ⇒ Material database ⇒ nextnano.NEGF database file

Note that this material database shares the same structure with the one of the nextnano.MSB code, which documentation can be found here: Material Database

Most of the default material parameters are taken from I. Vurgaftman, J. R. Meyer, L. R. Ram-Mohan, J. Appl. Phys. 89, 5815 (2001).

Some parameters can be overwritten in the input file, see section on <Material_Parameters> in the input file documentation.

 <!-- parameter that accounts for remote-band effects in 8-band k.p theory -->
S = 1+2F

The deformation potential

 <DeformationPotential Unit="eV">-7.2</DeformationPotential>

corresponds to a_c of Vurgaftman (i.e. for the conduction band only) in the isotropic approximation. It is used to calculate the shift of the conduction band edge due to strain. It is also used to calculate scattering by acoustic phonons (which is a very small effect, almost negligible in typical QCLs and RTDs).