QuantumATK Forum

QuantumATK => General Questions and Answers => Topic started by: grasim on March 2, 2013, 14:23

Title: a new model for Ni-Graphene-Ni MTJ with Gate Voltage
Post by: grasim on March 2, 2013, 14:23

Hi, I have set up a new model to study the question as decribed in
http://quantumwise.com/forum/index.php?topic=2201.0
In this model  DFT and Neumann boundary condition are used. And and I want to calculate the TMR vs different gate voltage.  Now it should be an interface structure, and there is a piece of Graphene in the middle Ni.  The model is periodicity out of the screen plane.
Should this model be correct? Thank you.

Title: Re: a new model for Ni-Graphene-Ni MTJ with Gate Voltage
Post by: Anders Blom on March 4, 2013, 09:46

When you are looking at a device model like this, it's a good idea to always repeat it 3x3 in A and B just to check how it looks. If you do that, you will find that the gate is repeated to, since there is always also a geometric periodic boundary condition in both A and B.

So the only chance this geometry is going to work is if you make a double-gate. In that case you can use periodic boundary conditions also for the Poisson solver.