Getting Started#

First steps#

We recommend downloading bundle packages containing compatible combination of nextnano++, nextnano³, nextnano.NEGF, and nextnanomat. Packages containing only nextnano.NEGF and nextnanomat are also available on our download site.

We recommend the following steps to kick off:

  1. first get familiar with the nextnanomat user interface using the nextnano++ tool and

  2. then have a look at nextnano.NEGF.

In particular, the template feature of the nextnanomat user interface is useful. Once you get familiar with the user interface, you are ready to start nextnano.NEGF simulations.

Note

If you have installed nextnano.NEGF separately from nextnanomat, you may need to manually set the path to the nextnano.NEGF.exe executable in nextnanomat ==> Tools ==> Options ==> Executable Windows ==> Path to nextnano.NEGF (C++) executable file for Windows.

Note

On Windows, please make sure to tick the checkbox in Windows File Explorer ==> View ==> File name extensions. Otherwise, you will only see:

  • nextnano.NEGF (without file extension .exe) and not

  • nextnano.NEGF.exe.

Sample input files can be found in the nextnano.NEGF/examples folder. We recommend first running the example Sirtori1994_doubleQW_3bands.negf. It calculates the equilibrium Green’s functions in a double quantum well, and runs within a few seconds. For QCLs, a recommended example to start with is THz_QCL_GaAs_AlGaAs_Fathololoumi_OptExpress2012_10K-FAST.negf. This input file runs fast (typically 5 minutes) and produces a current-voltage characteristics of a THz QCL. More accurate results can be obtained with the corresponding file THz_QCL_GaAs_AlGaAs_Fathololoumi_OptExpress2012-MEDIUM.negf. It takes more time (~2 hours) but produces much more realistic results by including the contribution of high-energy subbands. If the calculation takes much longer, your CPU might not be very fast or you do not have sufficient RAM (see How much memory do I need?).

We hope you enjoy using nextnano.NEGF.

Please let us know if you encounter any difficulty or experience any strange simulation results.

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