Author Topic: fundamental question  (Read 4987 times)

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Offline snowf

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fundamental question
« on: December 16, 2009, 10:03 »
Hi,everyone
I have three questions:
the difference of the first Transmission and the second,and the two value of the wavevector
these are seven datas corresponding to above six,what is the meaning of other.
I want to draw the relation of Transmission coefficient and Number of k-points,which datas I should chose?
thank you.

# Transmission Spectrum:: Conductance: 0.226882 uS
# K-Point Resolved spectra
# Energy (eV)     Transmission   DOS     PDOS    Transmission Eigenvalues
# ----------------------------------------------------------------
# WaveVector : -0.550648 -0.550648 0 1/Bohr
# Spin       : Up
# ----------------------------------------------------------------
   0.00000    0.000002      61.782      61.782    0.000002 6.32e-16 7.63e-20
# ----------------------------------------------------------------
# WaveVector : -0.492685 -0.550648 0 1/Bohr
# Spin       : Up
# ----------------------------------------------------------------
   0.00000    0.000007      97.426      97.426    0.000007 7.99e-16 8.79e-21
# ----------------------------------------------------------------
# WaveVector : -0.434722 -0.550648 0 1/Bohr
# Spin       : Up
# ----------------------------------------------------------------
   0.00000    0.000016      109.92      109.92    0.000016 2.58e-15 2.44e-21
# ----------------------------------------------------------------
# WaveVector : -0.376759 -0.550648 0 1/Bohr
# Spin       : Up
# ----------------------------------------------------------------
   0.00000    0.000030      129.67      129.67    0.000030 3.82e-13 1.06e-20
# ----------------------------------------------------------------
...........

Offline zh

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Re: fundamental question
« Reply #1 on: December 17, 2009, 03:56 »
Generally, the transmission coefficient t depends on the spin ([tex]\sigma[/tex]), wave vector (k), and energy (E), i.e., t([tex]\sigma[/tex], k, E). The commented line already tell us the meaning of each numerical data.  It is already told us these results printed here for the k-point resolved spectra.

Quote
# Transmission Spectrum:: Conductance: 0.226882 uS
This line gives the value of conductance. The conductance is obtained by its relationship with the transmission coefficient at the Fermi level (i.e., [tex]\sum_{\sigma, k}t(\sigma, k, E=0[/tex]). Here, maybe the non-spin-polarized calculation was carried out, so  the results only for spin up were printed out.

Quote
# Transmission Spectrum:: Conductance: 0.226882 uS
# K-Point Resolved spectra
# Energy (eV)     Transmission   DOS     PDOS    Transmission Eigenvalues
# ----------------------------------------------------------------
# WaveVector : -0.550648 -0.550648 0 1/Bohr
# Spin       : Up
# ----------------------------------------------------------------
   0.00000    0.000002      61.782      61.782    0.000002 6.32e-16 7.63e-20
In the last line, the first number is the energy value (i.e., here E=0.000 means the Fermi level), the 2nd number is the transmission coefficient for the wave vector (k =(-0.550648, -0.550648, 0,) 1/Bohr, this is given in cartesian coordination and 1/Bohr is the unit.), the 3rd number is the value of total DOS, the 4th number is the value of partial DOS, and the last two ones are the transmission eigenvalues (here, only two of transmission eigenvalues were printed out.).

For your last question, you may choose data in the first line for your plot.


Offline snowf

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Re: fundamental question
« Reply #2 on: December 17, 2009, 09:04 »
Thanks,but I could't understand the words:

For your last question, you may choose data in the first line for your plot.

please explain it detailed.

Offline Anders Blom

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Re: fundamental question
« Reply #3 on: December 17, 2009, 18:38 »
In general, we cannot offer support any more for the legacy product ATK 2.0.4, unless you have a recent maintenance contract.

To plot the relation between T and kx, ky in the newer product, using NanoLanguage, see http://quantumwise.com/forum/index.php?topic=84.0

As for your question, as I understood it, why there are 7 values but only 6 entries on the legend line ("Energy (eV)     Transmission   DOS     PDOS    Transmission Eigenvalues"), it's because there are two transmission eigenvalues (both of which are zero, however, since the transmission is also, basically, zero).