  The Empirical Tight Binding(ETB) method is widely used in atomistic device
simulations. The reliability of such simulations depends very strongly on the
choice of basis sets and the ETB parameters. The traditional way of obtaining
the ETB parameters is by fitting to experiment data, or critical theoretical
bandedges and symmetries rather than a foundational mapping. A further
shortcoming of traditional ETB is the lack of an explicit basis. In this work,
a DFT mapping process which constructs TB parameters and explicit basis from
DFT calculations is developed. The method is applied to two materials: GaAs and
MgO. Compared with the existing TB parameters, the GaAs parameters by DFT
mapping show better agreement with the DFT results in bulk band structure
calculations and lead to different indirect valleys when applied to nanowire
calculations. The MgO TB parameters and TB basis functions are also obtained
through the DFT mapping process.
