Boundary Condition at finite bias

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For a device simulation, when it is under the finite bias, I found the  default boundary  condition for the C direction (Left, Right) are both Dirichlet condition. To my knowledge, this condition means that 'The Hartree potential is zero at the boundary'. However, because the device is under finite bias voltage (that is, the chemical potential, or electropotential is different). Then, it seems that the Dirichlet condition can not apply to left-electrode-center-region interface and right-electrode-center-region at the same time ?  Should I change the default Dirichlet condition to other condition such as  Neumann?

Thank you.

[Petr Khomyakov]

In general, the Dirichlet boundary condition means some constant potential at the boundary, not necessary zero constant potential. Setting the electrode potentials in the electrode settings of the Device Calculator takes care of it.

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https://docs.quantumwise.com/manuals/technicalnotes/hartree_potential/hartree_potential.html

Thank you.
I obtain the explanation of Dirichlet condiction from the ATK maunual (see the above link). So minor correction may be neccesary to avoid more misunderstanding.

[Petr Khomyakov]

There is no mistake in the manual. In ATK, the default value is zero indeed, but it is possible to change it to an arbitrary potential value for device calculations by explicitly setting the left and right electrode potentials in the Electrode Parameters in the Device Calculator.