Integrated open software suite for nanoscale modeling version 1.03
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DFTB+XT open software package for quantum nanoscale modeling
DFTB+XT is an open source software package for
DFTB+XT is a general quantum transport code, able to work with both model and atomistic Hamiltonians.

DFTB+XT is an extended version of the DFTB+ code for model and atomistic quantum transport at nanoscale, many-body nonequilibrium phenomena, material & device modeling.
DFTB+ is a fast and efficient versatile quantum mechanical simulation software package. It is based on the Density Functional Tight Binding (DFTB) method, containing almost all of the useful extensions which have been developed for the DFTB framework so far. Using DFTB+ you can carry out quantum mechanical simulations similar to density functional theory but in an approximate way, typically gaining around two orders of magnitude in speed.

See About DFTB+ for further details.

DFTB+ and DFTB+XT is free and open software licensed under the GNU Lesser GPL version 3 or later.

DFTB+XT source code is based on the DFTB+ source code and LibNEGF source code (which itself is used in DFTB+ for transport calculations). Additionally, it suggests a number of new features, which are in the testing phase and may be included into the DFTB+ release later. The extended functionality of DFTB+XT is mainly focused on many-body quantum transport and applications in nanoscience, material and device modeling.

New features

In the current version of DFTB+XT we present the following new features.

  • Model Hamiltonians for transport calculations

    We introduced the possibility to read model Hamiltonians from external data files and use it with or without a geometry structure. This is especially important for many-body quantum transport problems.

  • Elastic dephasing

    Two models of elastic dephasing ("B├╝ttiker probe" and "vibronic dephasing") can be used now to include the dephasing and dissipation beyond the coherent Green function method. Thus, we made a new step towards realistic material and device modeling.

  • Application to STM spectroscopy

    We added new options to simplify and make faster the calculation of currents for systems with changeable geometry (like the STM setup). We also supply the python scripts for modeling of the scanning process over tip position and voltage.