BufferConstrain parameters
The parameters in this section are for buffer constrain.
calculation.bufferConstrain.isIncluded
keyword: calculation.bufferConstrain.isIncluded
possible values: true or false
default value: false
description: When the parameter is set as true, a drop of potential energy across the device due to the bias voltage will have been predicted, and the predicted value will be mixed into the calculated Hartree potential in order to apply a constrain on the potential drop over the device.
an example:
calculation.bufferConstrain.isIncluded = true
calculation.bufferConstrain.type
keyword: calculation.bufferConstrain.type
possible values: ‘hard’ or ‘soft’
default value: ‘hard’
description: The type of the constrain. When it is ‘hard’, the constrain is applied over the all device; the mixing weight decreases to 0 at the middle of the device. When it is ‘soft’, the constrain is only applied within the buffer region; the mixing weight decreases to 0 at the end of the buffer.
an example:
calculation.bufferConstrain.type = 'soft'
calculation.bufferConstrain.leadBufferLength
keyword: calculation.bufferConstrain.leadBufferLength
possible values: a double vector
default value: [5 5]
description: This parameter defines the buffer region adjecent to each lead unit cell, where no potential drop is expected, in other words, the potential is predicted to drop across the device without the buffer. The parameter is in the unit of angstrom.
an example:
calculation.bufferConstrain.leadBufferLength = [6 6]
calculation.bufferConstrain.mixingWeightWidth
keyword: calculation.bufferConstrain.mixingWeightWidth
possible values: a double vector
default value: [3.5 3.5]
description: The weight of mixing the predicted potential drop into the calculated Hartree potential is position dependent, and this parameter is for defining the shape of the weight which decreases from 1 to 0 within the given width. The parameter is in the unit of angstrom.
an example:
calculation.bufferConstrain.mixingWeightWidth = [4 4]
calculation.bufferConstrain.refSysObject
keyword: calculation.bufferConstrain.refSysObject
possible values: a file name of a saved cNanodcal object with 0 bias
default value: no default value
description: The parameter is to give the object of the system under 0 bias voltage which will be used as a reference.
an example:
calculation.bufferConstrain.refSysObject = ...
../0.0/NanodcalObject.mat