QuantumATK Forum
QuantumATK => General Questions and Answers => Topic started by: bubble on December 18, 2017, 15:13
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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.
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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.
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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.