QuantumATK Forum

QuantumATK => General Questions and Answers => Topic started by: deepak on January 27, 2012, 07:33

Title: band structure of device configuration
Post by: deepak on January 27, 2012, 07:33

how can i calculate the band structure of graphene nanoribbon device. I tried to do so but there in no band structure option in the Analysis. I m confused. Please help me out. I m attaching the screen shot.
Thanks

Title: Re: band structure of device configuration
Post by: kstokbro on January 27, 2012, 09:25

Since a device does not have periodic boundary conditions in 3D, the bandstructure of a device is not a well defined quantity and can therefore not be calculated.
Take the ATK device tutorial to learn about the available analysis options for a device.

Title: Re: band structure of device configuration
Post by: kaypu on October 9, 2012, 05:30

can atk show the  band structure of electrode in the system? how to do it?

Title: Re: band structure of device configuration
Post by: zh on October 9, 2012, 06:37

You should treat the electrode as a bulk system and then calculate the band structure.  That is to say, what you should do is the band structure a nanoribbon.  The calculation procedure for such system is already demonstrated in the manual.

Title: Re: band structure of device configuration
Post by: Anders Blom on October 9, 2012, 09:30

A few additional notes.

In the picture in the original post, the system is set up way too "minimalistic". The electrodes are too short in Z, as is the central region.

On the other hand, for the electrode band structure calculation you do indeed want the minimal electrode, to avoid zone folding but also to make the calculations faster.

There is a tool in VNL to extract the electrodes from the device configuration (a button on the left-hand side toolbar), but it doesn't reduce them to minimal. So the procedure I would recommend is to make a dopy of the device configuration, convert it to bulk (click the "Bulk" button), then again make a device from it, but this time with the minimal electrode (shortest possible length suggested in "Device From Bulk") and then finally extract the electrode using the "Split Device" button.

Title: Re: band structure of device configuration
Post by: kaypu on October 9, 2012, 12:31

got it
thanks professor zh and Anders