Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.

Schrodinger-Poisson Coupling for Heterostructures + Electric Potential Error

Please login with a confirmed email address before reporting spam

Hello,

I am performing a self-consistent SP calculation on a 1D multiple quantum well heterostructure. Neither of the example applications are heterostructures and I wanted to clarify how to do this in the Multiphysics nodes.

The SP Coupling Multiphysics node has a setting for user defined density of states effective mass. Should I employ two mulitphysics nodes (one for each material) or use one node and try to define some sort of piecewise function for the effective mass throughout the structure?

I was questioning my decision to use two separate multiphysics nodes because I get the following error-

Undefined value found. - Detail: Undefined value found in the stiffness matrix. There are 717 equations giving NaN/Inf in the matrix rows for the variable comp1.V.

under Stationary Solver 2: Solve for Electric Potential in the solver config for my SP Study and have been trying to figure out why it can't calculate the new potential. My boundary conditions in the ES physics are zero charge at one end and an electric potential set to half the bandgap of the cap/barrier material for Fermi-level pinning. My boundary conditions in the Schro. physics are zero flux at both ends. In my Schrodinger Eqn. Physics I defined to separate effective mass nodes (one for each material).

I know this is a lot in one post, but any help would be greatly appreciated.

Thank you,


0 Replies Last Post 18 dic 2019, 10:21 GMT-5
COMSOL Moderator

Hello Catherine O'Hearn

Your Discussion has gone 30 days without a reply. If you still need help with COMSOL and have an on-subscription license, please visit our Support Center for help.

If you do not hold an on-subscription license, you may find an answer in another Discussion or in the Knowledge Base.

Note that while COMSOL employees may participate in the discussion forum, COMSOL® software users who are on-subscription should submit their questions via the Support Center for a more comprehensive response from the Technical Support team.