Messages

31

General Questions and Answers / Re: how to get the table?

« on: June 22, 2009, 15:05 »

Thank you !

 To get the correct spectrum you must project the Hamiltonian onto the molecule atoms only;

When I perform the calculation, I just include the molecule atoms.

What is the real meaning of "Project the Hamiltonian onto the molecule atoms only"? Do I have to select the projection atoms manully? If yes, please tell me how to perform the calculation in detail.

http://quantumwise.com/documents/manuals/ATK-2008.10/chap.advtwoprobe.html#sect1.advtwoprobe.dos

I also have read the tutorial  of the spectrum caculation of li-h2-li system. In this tutorial, scf, projection_atoms = [3,4].

If I want to obtain the right spectrum, how to select the projection atoms. Does it should be include all of atoms of  the C nanowire?

I have tried to select the atoms in the follow script.  Please have a look at it, and tell me is right or not.
The Li atoms of  left or right  electrodes is 64. In the central region, the Li atoms is 96. And the C wire atoms is 307.

I want to Know if the calculation should include the Li atoms in the central region.

Thanks again for your reply!

32

General Questions and Answers / Re: how to get the table?

« on: June 22, 2009, 10:01 »

Hi, Ander Blom! I know MPSH = molecular projected self-consistent Hamiltonian. Can you tell me, in FIG 3 and FIG 5, If the value of circles and triangles are represent the value of projected Hamiltonian energy spectrum of two probe model.

I also calculate the projected Hamiltonian energy spectrum of my two probe model. From the calculated results, the homo - lumo gap is 0.18. As can we see from the energy spectrum, there are lots of values,and some of the values are equivalent. I also do not know the reason.

Now that there are so many values, if I want to plot the value, which one should be given, just as in FIG 3 and FIG 5?

(attached file is the calculated projected Hamiltonian energy spectrum)

Thanks!

33

General Questions and Answers / Re: how to get the table?

« on: June 21, 2009, 16:05 »

Hi,everyone! I have calculated the transmission eigenvalues of my two probe model. Attached is the results.To be honest, I do not understand the results. Can anyone tell me what is the real meaning of the results?

Moreover, fig 3 and fig 5 in physical review B 71,165316(2005) have plot the MPSH eigenvalues are marked with circles for DTB and with triangles for OPV3. I want to know if I calculated results is equal to the MPSH eigenvalues. However, the results are not like the value in FIG 3 and FIG 5. Plese tell me the differents of the results? And how to got the MPSH eigenvalues  in fig 3 and fig 5?

Thanks in advance!

34

General Questions and Answers / Re: how to get the table?

« on: June 19, 2009, 09:24 »

Thank you for your valuable and clear reply, Nori ! I will try again to calculate the transmission eigenvalues.

35

General Questions and Answers / how to get the table?

« on: June 19, 2009, 03:48 »

Hellow, everyone! I have been puzzling about the table 2 in Nano Lett. 2008 Nov;8(11):3662-7. Epub 2008 Oct 14.

I do not understand what is the real meaning of the first three Eigenchannels of the transmission? I want to know how to obtain the channel 1, channel 2 , channel 3 ,and the others?

In order to understand the table, I have try to calculate the transmission eigenstates and transmission eigenvalues of my two probe model, but the results are not like this.

In table 2, they also calculate the percentage probability of transmission, in my opinion, one channel should have a value, the wire should have lots of channels, so we can calculate the percentage. I don't know what I have said is right or not?

Can anyone tell me  how to distinguish the channel 1, channel 2 and channel 3.......? In other words, if I want to obtain the table, what should I do?

Thanks in advance!

36

General Questions and Answers / Wave functions of MPSH

« on: June 10, 2009, 04:45 »

Hellow, everyone! When I read the paper, I have see many picture of wave functions of MPSH states. If I have calculate the MPSH of a two probe model, I want to know how to got the picture. Can anyone tell me the methods? Thank you very much!

37

General Questions and Answers / When I want to save the two probe model, the problem occurs

« on: June 10, 2009, 04:30 »

Hi, everyone! I have build the two probe model, when I click SAVE/SAVE AS, the problem occurs. Attached is the warning picture. Can anyone help me to solve the problem? Thanks in advance!

38

General Questions and Answers / Re: Is the calculated results right?

« on: June 7, 2009, 11:25 »

Thank you very much! I will try with your suggestion.

And I also want to know the reasons of my second question. (2) In order to calculated the properties of two probe system, I want to know if the Li electrodes is appropriate for a C wire? Do I have to choose Au or other metals as the electrodes?

When we choose the electrodes, do we need pay attention to the atomic weight. In order to clearly distinguish the physical meaning of the two model, we should choose the eletrodes compared with the nanostructures. In other words, if the atom weight of the nanostructures is M, and atom weight of the electrodes is N. Do we need pay attention to keep the value of N-M OR M-N is very larger.

Thanks!

39

General Questions and Answers / Re: Is the calculated results right?

« on: June 7, 2009, 10:01 »

Ok, Nordland! Thank you! Did you have a look at my post file c(0.4V).txt. The current is 10-7A. I think the question is still with low applied voltages. Please have a look at it, and give me more explaintion. I really appreciate your views!

40

General Questions and Answers / Re: Is the calculated results right?

« on: June 7, 2009, 07:43 »

Hi,Nordland! At the begin of this subject is the calculated results, it includes current, transmission spectra and DOS!

Here I have also post a calculation with 0.4V of the two probe model. This question is still. Hope you have a look at it, and give your opinion here!

Thank you.

41

General Questions and Answers / Re: Is the calculated results right?

« on: June 7, 2009, 04:37 »

Hi,everyone! Now,I have some questions.

(1) As we can see clearly from the calculated results, with the applied voltage of 6V, the current value is 1.83148e-06A. The current is very larger as far as I know in the two probe calculation.

We can see from the transmission spectra, the coefficient is zero around the fermi level. From the DOS, there is electrons at the fermi level, but the electrons can not be transmitted through the central scattering region.

As far as I know, the current has been calculated by the Landauer formula in ATK. In Landauer formula, T(E,V_b) is the transmission coefficients in bais window.

Now that the transmission is 0 in the bais window, I don't understand how the current be got in the calculation. In other words, how to explain the larger current value ? Can anyone give me the explaination?

(2) In order to calculated the properties of two probe system, I want to know if the Li electrodes is appropriate for a C wire? Do I have to choose Au or other metals as the electrodes?

Thanks in advance!!

42

General Questions and Answers / Re: About MPSH

« on: June 3, 2009, 13:15 »

Thank you for your reply!

43

General Questions and Answers / Re: a picture

« on: June 3, 2009, 00:46 »

Thank you for your reminding ,Anders Blom! I really appreciate your reply.Good job!
 

44

General Questions and Answers / Re: a picture

« on: June 2, 2009, 18:02 »

Can anyone give me the answer as soon as possible? I have been looking forward to your reply!     Thanks in advance!

45

General Questions and Answers / Re: a picture

« on: June 2, 2009, 14:42 »

If we want to calculate the LDOS of a two probe system.How set the Quantum Numbers (k(A),K(B))? I have read the help file, but I can not understand it accurately. Can you give me some explain in detail? Thanks!