Messages

1

General Questions and Answers / How I can save the k-point resolved transmission coefficients

« on: August 12, 2010, 17:50 »

From the file Tutorial_Transmission_Coefficients.pdf downloading from ATK, I learn to how to get
the  k-point resolved transmission coefficients.

As shown in the following script, I can get the file FeMgO_ap_maj.png for the  k-point resolved transmission coefficients.

#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
from ATK.TwoProbe import *
import numpy
 
#------------------------------------
nc_filename = 'femgofe_antipara.nc'
Npoints = 25
energy = 0.*eV
#------------------------------------
 
Kxy = numpy.linspace(-0.5,0.5,Npoints)
K = []
for kx in Kxy:
    for ky in Kxy:
        K.append([kx,ky])
scf = restoreSelfConsistentCalculation(nc_filename)
# Spin-dependent version
trans_coeff = calculateTransmissionCoefficients(scf,energy,(K,Spin.Up))
# No spin
### trans_coeff = calculateTransmissionCoefficients(scf,energy, K)
T = trans_coeff.reshape(Npoints,Npoints)
 
def plotTEk(Kxy,T,title,filename):
    import pylab as P
    fig = P.figure()
    P.xlabel('kx')
    P.ylabel('ky')
    P.contourf(Kxy,Kxy,T,40,cmap=P.cm.Spectral)
    P.colorbar()
    P.axis([-.5,.5,-.5,.5])
    P.yticks(numpy.arange(-0.5,0.51,0.1))
    P.xticks(numpy.arange(-0.5,0.51,0.1))
    P.title(title)
    P.savefig(filename,dpi=100)
 
title = 'FeMgO, anti-parallel config, majority spin'
# Let us plot log(T) instead of T
plotTEk(Kxy,numpy.log(abs(T)),title,'FeMgO_ap_maj.png')

#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Now I would like to get the data file, and then I can plot the  k-point resolved transmission coefficients using my own plot tool, like gnuplot.

How can I change the above script to save  the  k-point resolved transmission coefficients as one isolated file?

2

General Questions and Answers / one basic question about eigenstate

« on: March 17, 2010, 21:58 »

Dear All,

  I have one basic question about eigenstate.
In some energy region,  transmission is zero,  and the corresponding eigenvalue should be zero.
My question is that i can  get the cooresponding eigenstate in these region?