bulk optmoziation

[naash]

does optimizing a device in bulk mode then using the optimized bulk  and switch it to device mode have any effect on transmission or IV curve

[zh]

The applied voltage may lead to a change in the atomic structure of device. At the current stage, this effect is neglected.

[Nordland]

does optimizing a device in bulk mode then using the optimized bulk  and switch it to device mode have any effect on transmission or IV curve

It can have an effect, but if the bias is low in the IV curve the effect is properly smaller. The optimization of bulk does not take into account the external field that comes from the biases. This is how I do it normally: I optimize the device central region as a bulk system (remembering constraint) as a start. Then I apply a biases on this system of perhaps 1 Volt, and then depending on how much time I have I do one of the following:

• Calculate the forces - and if they are small I accept it
• Or I optimize the structure for this bias, and calculate the Transmission spectrum for this structure and compare it to the bulk optimized. If they are very close I choose to negect this effect, and dont optimize the geometry further