Messages

1

General Questions and Answers / Whats the difference between band structure energy and toal energy

« on: July 23, 2009, 05:34 »

Part of my geometry opt output. Ebs(in red), according to the reference, meaning "band structure energy, i.e. the sum of the energies of all states weighted with their respective occupation". Then what is the meaning of "Total Energy"? Why these two values are different? Here, Ebs = -2957.3953 eV, while Total Energy = =-14817.9986 eV

# sc 21 : Fermi Energy =   -0.32537 Ry Ebs = -217.36284 Ry  dRho =  9.0874E-05
# Geometry optimization step : 69
# Total Energy           =-14817.9986 eV

2

General Questions and Answers / [help] Which electrode material should I choose for SiO2

« on: May 19, 2009, 04:17 »

Should I use Al or Si?

I focus on the SiO2 strucuture change, so that electrode material is not that important so long it represents the right physical meaning. In the experimental, we often use poly-Si, but since it is not possible to simulate poly-Si/SiO2/poly-Si stack. So I am thinking whether it is appropriate to use Al or Si.

3

General Questions and Answers / Re: question on two-probe model setting up

« on: May 19, 2009, 04:10 »

Hi all,

the problem has been solved, thanks.

4

General Questions and Answers / question on two-probe model setting up

« on: May 12, 2009, 13:53 »

I followed the VNL version 200810 tutorial, to set up a Li-H2-Li two-probe system. But I found that the position of the right electrode can not be adjusted indivisually. Everytime I tried to move the right electrode closer to H2 molecule in the middle, the whole left electrode and H2 molecule will move, too.

Please see attached figures.
1st step: I adjusted the distance between H2 to the left electrode


2nd step: I want to select the Li atom nearest to H2 in the right electrode, but everytime all the middel region in white was selected


3rd step: I use "translate" commond, the whole unwanted region moved toward right


If this problems happen to every case, how can we set up a two-probe system successfully? Pls help. Thanks in advance.

5

General Questions and Answers / Re: why cant I drag-and-drop models from crystal cupboard to atomic manipulator

« on: May 12, 2009, 09:33 »

I resolved the problem already.

My mistake is that I opened Atomic Manipulator screen first. Actually all I need to do is just drag-and-drop models to the Atomic Manipulator icon in the tool bar.

6

General Questions and Answers / why cant I drag-and-drop models from crystal cupboard to atomic manipulator

« on: May 12, 2009, 09:14 »

Hi All,

I can not drag-and-drop models from crystal cupboard to atomic manipulator. Nothing changed in the atomic manipulator screen. But I can drag-and-drop models from crystal cupboard to Nanoscope screen. I re-install my VNL several times but this problem still bugs me.

Thank you if you could give me some advices.