To take advantage of the default settings detailed below, use the Model Wizard or the
Add Study button in the ribbon/toolbar of the graphical user interface. A study step added by right-clicking a Study node does not include any default settings suggested by the physics.
The default option for the Eigenfrequency (Eigenvalue) search method list is
Manual, because for a completely new problem, it is often necessary to use this option to find the range of the eigenenergies and a rough estimate of the number of eigenstates. Make sure that the
Unit list is left as blank (default).
Once the range and number are found, switch to the Region search option with appropriate settings for the range and number of eigenvalues, in order to ensure that all significant eigenstates are found by the solver.
Make sure the Unit list is left as blank (default).
If there are extra domain or boundary conditions used to obtain the initial value for the fully coupled problem, remember to disable them here. For example, see the schrodinger_poisson_nanowire tutorial model, where the Thomas-Fermi solution is used as the initial condition, and the space charge density contribution from the Thomas-Fermi approximation is disabled here.
The default option for the Termination method drop-down menu is
Minimization of global variable, which updates a table displaying the history of a global error variable after each iteration during the solution process. This provides a good indication of the solution process to monitor whether the iteration is converging.
The default expression for the Global variable input field uses the built-in global error variable
schrp1.global_err, which computes the max difference between the electric potential fields from the two most recent iterations, in the unit of V, as discussed in the section
Charge Density Computation for the Schrödinger-Poisson Coupling multiphysics node earlier. Note that the prefix for the variable, in this case
schrp1, should match the
Name input field of the Schrödinger-Poisson Coupling multiphysics node. (See section
Settings) Setting the
Absolute tolerance to
1e-6 thus means the iteration ends after the max difference is less than
1 uV.
Use the Auxiliary sweep option to solve for a set of parameters, for example, in the
schrodinger_poisson_nanowire tutorial model, it is used to solve for a set of azimuthal quantum numbers. The total particle density will be computed using the statistically weighted sum of all the eigenstates for all parameters.