=============================================== *** Wannier-Transport (WanT) package *** =============================================== See http://www.wannier-transport.org for news and details. ========================== ABOUT WanT ========================== WanT is an open-source, GNU General Public License suite of codes that provides an integrated approach for the study of coherent electronic transport in nanostructures. The core methodology combines state-of-the-art Density Functional Theory (DFT), plane-wave, norm-conserving pseudopotentials calculations with a Green's functions method based on the Landauer formalism to describe quantum conductance. The essential connection between the two, and a crucial step in the calculation, is the use of the maximally-localized Wannier function representation to introduce naturally the ground-state electronic structure into the lattice Green's function approach at the basis of the evaluation of the quantum conductance. Moreover, the knowledge of the Wannier functions of the system allows for the direct link between the electronic transport properties of the device with the nature of the chemical bonds, providing insight onto the mechanisms that govern electron flow at the nanoscale. The WanT package operates, in principles, as a simple post-processing of any standard electronic structure code. The WanT code is currently interfaced to the codes in the Quantum-ESPRESSO distribution (http://www.quantum-espresso.org, http://www.pwscf.org). ========================== WanT FEATURES ========================== WanT calculations will provide the user with: - Quantum conductance spectrum for a bulk (infinite, periodic) system and for a lead-conductor-lead geometry - Density of states spectrum in the conductor region - Centers and spreads of the maximally-localized Wannier functions of the system See also the WanT User's Guide in docs/want_manual.pdf ========================== TECHNICAL NOTES ========================== - Installation procedure is reported in the ~want/docs/README.install file; - ~want/docs/README_<prog>.input description of the input file for program <prog>; - ~want/docs/README summarizes the documentation included in the WanT package; See also the WanT User's Guide in docs/want_manual.pdf ========================== CREDITS ========================== See file ~want/docs/CREDITS for the details. ========================== TERMS OF USE ========================== Although users are not under any obligation in the spirit of the GNU General Public Licence, the developers of WanT would appreciate the acknowledgment of the effort to produce such codes in the form of the following reference: In the text: "The results of this work have been obtained using the WanT package.[ref]" In references: "[ref] WanT code by A. Ferretti, B. Bonferroni, A. Calzolari, and M. Buongiorno Nardelli, http://www.wannier-transport.org. ========================== DISCLAIMER ========================== While the developers of WanT make every effort to deliver a high quality scientific software, we do not guarantee that our codes are free from defects. Our software is provided "as is". Users are solely responsible for determining the appropriateness of using this package and assume all risks associated with the use of it, including but not limited to the risks of program errors, damage to or loss of data, programs or equipment, and unavailability or interruption of operations. Due to the limited human resources involved in the development of this software package, no support will be given to individual users for either installation or execution of the codes. Finally, in the spirit of every open source project, any contribution from external users is welcome, encouraged and, if appropriate, will be included in future releases. ========================== LICENCE ========================== All the material included in this distribution is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. These programs are distributed in the hope that they will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.