Print Page - Script for calculating the effective mass in semi-conductors.

QuantumATK => Scripts, Tutorials and Applications => Topic started by: Nordland on February 17, 2009, 00:14

Title: Script for calculating the effective mass in semi-conductors.
Post by: Nordland on February 17, 2009, 00:14

If you want to calculate the the effective mass of the electrons and holes in a semi-conductor,
I have created a small script for helping your in doing so. I have attached it to this post.

The script has been updated in a new improved version for support of anisotropic and/or indirect band gap semi-conductors.
And I have modified the tutorial to be on Si, since I could find experimental value of this material.
( However it should be noted, that one must manually enter k-points around which it should evaluate the effective mass,
and if the minimum is present at several places in the brillouin zone, the constant MC and MH must be adjusted represent this.
For instance in Si the lowest point of the conducting band is located 6 places in the brillouin zone, and hence MC must be set to 6)

Simple perform a calculation, and store the results in a NetCDF file,
and edit the script effective_mass.py to point at this netcdf file, and the run it as normal:
atk effective_mass.py

It will produced the following output ( based on a quick Si calculation i maded):

Quote

----------------------------------------------------------------------
# Electron effective mass
# ---> E = 0.238248813366
# ---> Conductivity = 0.25471464737 me
# ---> Density of states = 1.17006025908 me
# ---> Longitudinal = 1.3419675337 me
# ---> Transverse (1) = 0.165647613285 me
# ---> Transverse (2) = 0.200168158579 me
----------------------------------------------------------------------
# Hole effective mass (1)
# ---> E = -0.23358258646
# ---> Conductivity = 0.641102831335 me
# ---> Density of states = 0.641102831335 me
# ---> Longitudinal = 0.641102831305 me
# ---> Transverse (1) = 0.64110283176 me
# ---> Transverse (2) = 0.64110283094 me
----------------------------------------------------------------------
# Hole effective mass (2)
# ---> E = -0.233582586849
# ---> Conductivity = 0.64110283086 me
# ---> Density of states = 0.64110283086 me
# ---> Longitudinal = 0.64110283089 me
# ---> Transverse (1) = 0.641102830435 me
# ---> Transverse (2) = 0.641102831255 me
----------------------------------------------------------------------
# Hole effective mass (3)
# ---> E = -0.233582587149
# ---> Conductivity = 0.0926545669658 me
# ---> Density of states = 0.0926545669658 me
# ---> Longitudinal = 0.0926545669658 me
# ---> Transverse (1) = 0.0926545669658 me
# ---> Transverse (2) = 0.0926545669658 me
----------------------------------------------------------------------

Silicon has density of states effective mass of 1.08, conductivity effective mass of 0.26, and average hole mass of 0.56,
and I have collected the numbers in a small table below, and I think the agreement is pretty good.

Effective Mass	Experimental	Calculation	Error
Density of States	1.08	1.17	0.09
Conductivity	0.26	0.254	0.006
Hole (average)	0.56	0.46	0.1

Title: Re: Script for calculating the effective mass in semi-conductors.
Post by: Roc on February 23, 2009, 09:41

Dear Nordland ，

When I run these scripts " znse.py and effective_mass.py" , I get the slight different result from yours. as follows,
----------------------------------------------------------------------
# Electron effective mass = 0.174335561971 me
----------------------------------------------------------------------
# Hole effective mass (1) = 2.32687348618 me
# Hole effective mass (2) = 2.11284900262 me
# Hole effective mass (3) = 0.155049857542 me
----------------------------------------------------------------------
# Average hole effectiv mass = 1.53159078212 me
----------------------------------------------------------------------

what's the reason for that? (I run the scripts by the version of 2008,10)

Another, whether does it get different results for one same script by different version like 2008,02 or 2008,10

thanks.

Title: Re: Script for calculating the effective mass in semi-conductors.
Post by: Nordland on February 23, 2009, 11:45

The difference is very small, and when it is this order it can come from many things, however it is not anything to be worried about.

The platform, windows/linux, and the computer type (32bit/64bit), and many other factors can introduced
these very small deviations, when comparing results perform on machine compared to another.

I have run my example using ATK 2008.10, but I have not observed (and is not aware of ) that should change ATK 2008.02 from ATK 2008.10
in terms of results, when it comes to standard DFT.

Title: Re: Script for calculating the effective mass in semi-conductors.
Post by: rosen on March 6, 2009, 04:45

Thank you Nordland, but the script seems can only calculated the effectivemass in the G point, if there is an indirect bandgap material, it is improper to use this script, I have revised some of the code in this script to do calculate the effectivemass in an indirect bandgap material, but the result is no so satisfied:
Direct Band Gap = 6.97405383307 eV
Indirect Band Gap = 6.69934035399 eV
----------------------------------------------------------------------
# Electron effective mass = 0.0219170891857 me
----------------------------------------------------------------------
# Hole effective mass (1) = 0.069356447541 me
# Hole effective mass (2) = 0.0345840434497 me
# Hole effective mass (3) = -2.93394832023 me
----------------------------------------------------------------------
# Average hole effectiv mass = -0.943335943081 me
----------------------------------------------------------------------

(the experimental value of electron effectivemass for alpha SiO2 is 0.5me, and the effective hole mass is 0.38m)

is there anything wrong with my revised script?

Title: Re: Script for calculating the effective mass in semi-conductors.
Post by: Nordland on March 6, 2009, 12:42

The script has a variable callled kpoint, it is set to Gamma now, but can be set to anything, however the script will calculate the effective mass centered around this point. This means for indirect bandgap semiconductors, you will get bad results as the effective mass of the electrons and holes have to be calculated a different k-points, however if you can wait a couple of hours I will try to generalize it to handle indirect semi-conductors correctly.

Title: Re: Script for calculating the effective mass in semi-conductors.
Post by: rosen on March 6, 2009, 14:31

Quote from: Nordland on March 6, 2009, 12:42

if you can wait a couple of hours I will try to generalize it to handle indirect semi-conductors correctly.

;)

Title: Re: Script for calculating the effective mass in semi-conductors.
Post by: Nordland on March 6, 2009, 14:53

Progress update:

For Silicon I have perfect results, but for SiO2 I have some issues..... :) - trying to resolve this before posting........

Title: Re: Script for calculating the effective mass in semi-conductors.
Post by: rosen on March 12, 2009, 15:11

Is there any Progress?

Title: Re: Script for calculating the effective mass in semi-conductors.
Post by: Nordland on March 12, 2009, 21:57

Well, yes :) - but the results for SiO2 is not very good - perhaps it requires some parameter tweaking.

Title: Re: Script for calculating the effective mass in semi-conductors.
Post by: Nordland on March 14, 2009, 23:10

Rosen, I have reposted the first post with a new script and a new example.

I have found out that it is needed to make sure that the fermi level is very well converged in order to get good effective masses in terms of kpoints.
I use 15,15,15 and it gives good results.

Title: Re: Script for calculating the effective mass in semi-conductors.
Post by: rosen on March 15, 2009, 05:18

Thank Nordland, I will try to do it in SiO2

Title: Re: Script for calculating the effective mass in semi-conductors.
Post by: rosen on March 18, 2009, 08:58

in the effective mass calculation,
what is the physical meaning of the Conductivity effectivemass and the Density of states effectivemass?

Quote

Code

print '# Electron effective mass' 
print '# ---> E                     = %10s'%(b[step])
print '# ---> Conductivity          = %10s'%(3.0 * (abs((1/ml._value()) + 1/mt1._value() + 1/mt2._value()))**(-1) * me)
print '# ---> Density of states     = %10s'%((MC)**(2.0/3.0) * (ml._value()*mt1._value()*mt2._value())**(1.0/3.0) * me)

in wikipedia, the effectivemass is given for one definition.
http://en.wikipedia.org/wiki/Effective_mass_(solid-state_physics)
besides that, I have do a calculation of the Si with (15, 15, 15) mesh, the band structure (see attach) didn't have 6 lowest point of the conducting band in the brillouin zone?

Title: Re: Script for calculating the effective mass in semi-conductors.
Post by: Nordland on March 18, 2009, 10:53

Hey Rosen
Instead of me trying to explain the physical meaning, I have found two good references, the first
one is on the density of states effective mass. This is the most common printed in papers,
however for conductivity is more convinent to use the conductivity effective mass.

Paper with a note on conductivity effective mass. (http://mems.caltech.edu/courses/EE40%20Web%20Files/Supplements/01_Effective_Mass.pdf)
Paper on the density of states effective mass (http://www.ecse.rpi.edu/~schubert/Course-ECSE-6968%20Quantum%20mechanics/Ch12%20Density%20of%20states.pdf)

The lowest point in your bandstructure is located at (X,0,X), where X is rougly 0.42156, however there the following six points (0,X,X), ( X,0,X), (X,X,0), (0,-X,-X), (-X, 0, -X), (0, -X, -X) are equivalent in FCC, and hence MC becomes 6 for this point.

I hope this clarifies my ramblings :)

Title: Re: Script for calculating the effective mass in semi-conductors.
Post by: rosen on March 26, 2009, 03:48

Hi Nordland
I have tested your script with the BaTiO3, this model have 5 atoms.
the calculated bandstruture is attatched below.
for the cubic phase, both the conductiviey and DOS electron effectivemass gave 4.57579367772 me, but the experimental value for this phase is about 0.5 me.
and for the tetragonal phase, the
# ---> Conductivity = 0.487857138832 me
# ---> Density of states = 0.805148177393 me
I have two question:
firstly, from the bandstructure, the curvature at the CBM in G (0. 0. .0.) is almost the same, why the electron effectivemass have so large difference.
secondly, in the script, the experssion for the DOS effectivemass is

Code

print '# ---> Density of states     = %10s'%((MH)**(2.0/3.0) * (abs(ml._value()*mt1._value()*mt2._value()))**(1.0/3.0) * me)

,
but according to the paper you give us Paper with a note on conductivity effective mass.http://mems.caltech.edu/courses/EE40%20Web%20Files/Supplements/01_Effective_Mass.pdf (http://mems.caltech.edu/courses/EE40%20Web%20Files/Supplements/01_Effective_Mass.pdf), it should be

Code

 Density of states     = %10s'%((MH)**(3.0/2.0) * (abs(ml._value()*mt1._value()*mt2._value()))**(1.0/3.0) * me)

,
it will affect the result of Si, but has no influence on the BaTiO3 here.

Title: Re: Script for calculating the effective mass in semi-conductors.
Post by: Nordland on March 26, 2009, 07:28

Hey Rosen.

Thanks for testing my script and correcting my bugs :) - I will upload new version soon.

I think I know why there is a difference between the two phases - it is properly an artifact, but i think that I can explain the two effective mass from the bandstructure.

In the cubic phase at the Gamma point ( to the left most of your bandstructure ) there are two bands - one which is relative heavy perhaps roughly 4.0 - 7.0 ( the very flat one ) and one that is order of 0.5 - 1.0 ( the normal shaped one ).
The bands appears to be very close and perhaps degenerated at the gamma point, and perhaps there we end up with the wrong effective mass.

However in the tetragonal phase there is a spliting between these two bands, and then we don't have this issue of these two bands mixing in together.

I will try rerunning your calculation with the aim of finding out the differences :)

Title: Re: Script for calculating the effective mass in semi-conductors.
Post by: Quantamania on May 4, 2009, 02:51

I have read the papers describing the effective mass calculations posted in this thread. However, they are for three-dimensional crystals.

My research, which was recently approved by my proposal committee last Wednesday, revolves around pi-stacking and modeling their electron transport properties. I have made some interesting findings regarding their band structures, how they behave under phonon movement through them, and how their properties change from small molecular clusters to bulk pi-stack periodic structures.

Pi-stack structures are remarkably simple one-dimensional conducting wires. Based on their band structures, three k-points in one layer are the same, while another three k-points are also equal in a separate layer. These layers, I define as KGM and HAL, have different periodicity in Bloch wavefunctions. This difference produces the energy changes seen in their band structures (the example I attached is for benzene at 4 angstroms apart).

The picture below is the pi-stack crystal model I am using, a hexagonal crystal.
(http://i683.photobucket.com/albums/vv193/Quantamania/benzenecrystal.jpg)

How can the equations for conductivity, effective masses, and other properties in the script be adapted for one-dimensional conducting wires? I tried to apply the script to benzene pi-stacks, but got errors that prevented me from getting the numbers.

Can you please explain to me the changes that I would need to make in order to use the equations? The band structure of a pi-stack shows inflection at anytime crystal momentum moves from the KGM layer to the HAL layer or vice versa. The bandwidth inside the layers is essentially zero, and distance between rings controls the bandwidth between k-point layers. This gives us a conducting system with both a direct band gap and indirect band gap, each represented by intramolecular and intermolecular conduction. The direct band gaps in the KGM and HAL layers are quite insensitive to inter-ring distance, but the indirect band gap is especially sensitive to such effects, so its properties are highly tunable in this respect.

This would really help with my research as it currently stands.

Title: Re: Script for calculating the effective mass in semi-conductors.
Post by: Nordland on May 4, 2009, 07:19

I am properly wrong - but I don't think there is much to gain from investigating the effective mass in this kind of system. The effective mass approximation assumes, that the bands are parabolic around a minimum energy. This is the case for most three dimension crystals, but it can also be true for 1d or 2d systems.

Since your energy bands are technical flat with very little sign of parabolic nature, I think I would go straight ahead and use the standard NEGF transport calculation.

Title: Re: Script for calculating the effective mass in semi-conductors.
Post by: Nordland on May 4, 2009, 07:20

On a note, I should say, that I could generalized the script to be able to deal with 1d structures, and it would properly be pretty good for determine the bands gaps, but the effective mass in your system will still be a fishy :)

Title: Re: Script for calculating the effective mass in semi-conductors.
Post by: Quantamania on May 4, 2009, 15:12

I have previously tested the NEGF methods on these pi-stacks and junctions built from them, but have yet to see if known equations for effective mass can work on them.

The flatness of the pi-stack bands arises from the degeneracy of k-points, an effect imposed by the large dimensions of the rhombi making up the faces of the crystal. However, they are not flat across K-H, Gamma-A, or M-L. At the midpoints of these lines is the inflection point, where the slope of the band changes. Based on Roald Hoffmann's intuitive analysis of solid-state physics, the bands I have are behaving the way predicted by purely p-orbital arrangements. They start at a high energy, then lose energy as phase of adjacent orbitals is flipped in a continuous manner.

Initially, at K, the slope of the band is zero. At P (the midpoint of K-H), this slope is the greatest (most negative). It is also where the second derivative becomes zero. The slope begins to increase back up to zero as it goes to H once it passes P. The same thing holds for Delta (between Gamma and A) and the midpoint between M and L (do you know the symbol for it?). So I get three bandwidth regions if I use the default k-point set (G-M-L-A-G-K-H-A), since I have M-L, A-G, and K-H in that pathway. The example I posted in the last post was done using the same k-point pathway as the graphite calculations I did earlier. I did notice the non-parabolic behavior of these bands. What should we do in these instances?

Title: Re: Script for calculating the effective mass in semi-conductors.
Post by: Anders Blom on May 4, 2009, 15:29

The M-L path is called U.

I don't think the concept of effective mass applies in this case. It's a quantity used in simpler models, where the band structure is close to parabolic, such that you don't need the detailed band structure, but it suffices to use a simplified picture of it, i.e. a perfect parabola. If the band structure doesn't look like that, there is no point in trying to compute an effective mass, since it cannot be used for anything meaningful...

Title: Re: Script for calculating the effective mass in semi-conductors.
Post by: Quantamania on May 4, 2009, 23:37

Thanks for the clarification. The bands that I generally get tend to be non-parabolic, but rather sigmoid. However, if we look at the segments, K-P and P-H, they resemble parabolas. The same thing holds for M-U, U-L, Gamma-Delta, and Delta-A segments of the band structure. What should we do in this situation? Thus, it seems that the useful information we have include these right now:

Bandwidth of valence and conduction bands between k-point layers (K to H, Gamma to A, M to L)
Direct band gaps (between valence and conduction bands within KGM and HAL layers)
Indirect band gap (highly tunable with inter-ring distance, represented by Delta, U, and P lines of the Brillouin zone)
General slope behavior of valence and conduction bands (do they run in opposite directions or the same directions?)

Can you think of any other properties that can be gleaned from the simple pi-stack model? If so, I would like to consider them for my dissertation work.

Title: Re: Script for calculating the effective mass in semi-conductors.
Post by: Quantamania on May 11, 2009, 22:59

I have some new findings regarding my pi-stack structures...they are quite elastic. That means they have small energy barriers against phonon movement, but have stable structures consisting of equal inter-ring distances.

The method I used to deduct this was to perform calculations using GAUSSIAN03 with the same models I am discussing here. As before, I have a periodic box for the arenes, with room for two molecules. This supercell allows me to simulate phonon modes in pi-stack arrays. The method I use for generating these phonons is shown below:

(http://i683.photobucket.com/albums/vv193/Quantamania/LOphononpicture.jpg)

When the phonon is mediated by the arenes, the energy levels take on a parabolic dispersion curve! The origin of this curve is the nonlinearity of molecular orbital energies relative to inter-ring distances. The phonon produces two different inter-ring distances in the array, X1 and X2. X1, the shorter distance, produces much smaller HOMO-LUMO separations than X2, the longer distance, does. The rate of change towards X1 is greater than that towards X2 during the phonon movement. Thus, I have a finite effective mass for phonon-mediated transport through pi-stacks. The dispersion curve example I attached is for fluorobenzene, a typical example. I have observed this feature for many arenes and heterocycles. I can change where the dispersion curve goes by adding ionic functional groups to the rings, inducing antiaromaticity in the molecules, making the molecules radicals, or turning the molecules into pairs of cation/anion heterocycles. Elemental substitution, neutral functional groups, and mixing neutral species do not affect the direction of the typical dispersion curve, but they do change effective masses and initial molecular orbital energies.

Elasticity in lattices is essential for phonon-electron interactions, and since I have band gap narrowing under phonon movement, the array is not stable towards local dimer formation. This means that the phonon must leave the array somehow, once it has entered the system. It is not trapped efficiently by the arenes, because the energy variation is simply too small. Calculations using statistical thermodynamics have shown that the average temperature required for a 0.2 angstrom disturbance is well below 100 kelvins for most arene or heterocycle arrays. I have also verified the quality of fit for the parabolic curves using student t-test methods, showing that the dE2/dk2 term and hence effective mass obtained from it are very statistically significant.

What is your take on these findings? I feel that they do explain previous findings done with DNA, which one of the molecules I tested is a good nucleobase mimic.

Title: Re: Script for calculating the effective mass in semi-conductors.
Post by: voves on June 12, 2009, 15:23

Hi again,
I am calculating hole eff. masses in the strained InSb. If I understand, your script calculates long. and transv. eff. mass in the 100 and 010 (and 001) directions along A,B, and C vectors. But to calculate eff. mass in a warped band we need to average along 111 as well? Could you explain it or update the script, please?

1st and 2nd (N=1,2) eff. masses are almost the same for the unstrained InSb from your script (the same as for your Si example).

Jan

Quote from: Nordland on February 17, 2009, 00:14

If you want to calculate the the effective mass of the electrons and holes in a semi-conductor,
I have created a small script for helping your in doing so. I have attached it to this post.

The script has been updated in a new improved version for support of anisotropic and/or indirect band gap semi-conductors.
And I have modified the tutorial to be on Si, since I could find experimental value of this material.
( However it should be noted, that one must manually enter k-points around which it should evaluate the effective mass,
and if the minimum is present at several places in the brillouin zone, the constant MC and MH must be adjusted represent this.
For instance in Si the lowest point of the conducting band is located 6 places in the brillouin zone, and hence MC must be set to 6)

Simple perform a calculation, and store the results in a NetCDF file,
and edit the script effective_mass.py to point at this netcdf file, and the run it as normal:
atk effective_mass.py

It will produced the following output ( based on a quick Si calculation i maded):
Quote
----------------------------------------------------------------------
# Electron effective mass
# ---> E = 0.238248813366
# ---> Conductivity = 0.25471464737 me
# ---> Density of states = 1.17006025908 me
# ---> Longitudinal = 1.3419675337 me
# ---> Transverse (1) = 0.165647613285 me
# ---> Transverse (2) = 0.200168158579 me
----------------------------------------------------------------------
# Hole effective mass (1)
# ---> E = -0.23358258646
# ---> Conductivity = 0.641102831335 me
# ---> Density of states = 0.641102831335 me
# ---> Longitudinal = 0.641102831305 me
# ---> Transverse (1) = 0.64110283176 me
# ---> Transverse (2) = 0.64110283094 me
----------------------------------------------------------------------
# Hole effective mass (2)
# ---> E = -0.233582586849
# ---> Conductivity = 0.64110283086 me
# ---> Density of states = 0.64110283086 me
# ---> Longitudinal = 0.64110283089 me
# ---> Transverse (1) = 0.641102830435 me
# ---> Transverse (2) = 0.641102831255 me
----------------------------------------------------------------------
# Hole effective mass (3)
# ---> E = -0.233582587149
# ---> Conductivity = 0.0926545669658 me
# ---> Density of states = 0.0926545669658 me
# ---> Longitudinal = 0.0926545669658 me
# ---> Transverse (1) = 0.0926545669658 me
# ---> Transverse (2) = 0.0926545669658 me
----------------------------------------------------------------------

Silicon has density of states effective mass of 1.08, conductivity effective mass of 0.26, and average hole mass of 0.56,
and I have collected the numbers in a small table below, and I think the agreement is pretty good.

Effective Mass Experimental Calculation Error
Density of States 1.08 1.17 0.09
Conductivity 0.26 0.254 0.006
Hole (average) 0.56 0.46 0.1

Title: Re: Script for calculating the effective mass in semi-conductors.
Post by: Nordland on June 12, 2009, 20:47

I will try to look into how to modify the script :)

Title: Re: Script for calculating the effective mass in semi-conductors.
Post by: Nordland on June 13, 2009, 17:33

I think you can do the following, if the effective mass has to be evaluated around the Gamma point.

Instead of giving the exact Gamma point, you will give the value (1e-6,1e-6,1e-6), then it will still fit the effective mass to the Gamma point, but the longitudinal effective mass will be in the
direction of 111.

Title: Re: Script for calculating the effective mass in semi-conductors.
Post by: voves on June 15, 2009, 11:09

Thanks, but I´m afraid, that the second derivatives will be calculated still along the A,B,C reciprocal lattice vectors.
I´m going to try it.

Jan

Title: Re: Script for calculating the effective mass in semi-conductors.
Post by: Nordland on June 15, 2009, 11:17

The second derivative for the longitudinal effective mass is calculated along the line from the Gamma point to the given in the script,
and it will then make a polynomial fit around given point to get the effective mass.

Therefore if the value (1e-6,1e-6,1e-6) is given then the longitudinal effective mass will be evaluate in this direction. The transverse effective mass will
then be the directions perpendicular to this direction.

So I think it should work.

Title: Re: Script for calculating the effective mass in semi-conductors.
Post by: Anders Blom on June 16, 2009, 21:49

Some caution is required. The 111 direction is not necessarily the same as (1,1,1) in units of the primitive reciprocal lattice vectors. The "111" direction refers to the corresponding conventional system, thus in each case one needs to consider which combination of the primitive vectors that make up this "Cartesian" direction. For fcc, it is towards the X-point at (1,1,1)/2, i.e. the relevant point to use in this script would rather be (1e-6,0,1e-6).

Title: Re: Script for calculating the effective mass in semi-conductors.
Post by: voves on June 17, 2009, 10:04

Thanks, I found a script in the band structure tutorial. It shows the symetry points very well.

Title: Re: Script for calculating the effective mass in semi-conductors.
Post by: Anders Blom on June 17, 2009, 10:20

Please note that the symmetry points for tIn (body-centered tetragonal) and the orthorhombic ones are under evaluation. I just found some mistakes in them. I will post an update as soon as possible.

Title: Re: Script for calculating the effective mass in semi-conductors.
Post by: Anders Blom on August 2, 2011, 15:51

There is now a Custom Analyzer for computing the effective mass with ATK 11.2, with an associated tutorial (http://quantumwise.com/publications/tutorials/mini-tutorials/135)! Enjoy 8)

The new script is "less intelligent", the task of deciding the relevant directions is put on the user instead. It was the only way one could avoid either having an overly complex script which tried to do a lot of guesswork (which probably just fails in some cases anyway) or a pure Python workflow. But in the end it's not more difficult to use the new Analyzer than the old script (in fact simpler in many ways), it just doesn't do all masses at once, you have to do a bit more arithmetic yourself :)

Title: Re: Script for calculating the effective mass in semi-conductors.
Post by: zegna on September 22, 2012, 12:40

Hi to all!
I am new at this forum.
This method of calculating the effective mass is only applied to Si or can be applicaple on other semi,for example Silica(dioxide of silicon)?

If not,how could i calculate the effective mass of electrons and holes on silica?

Thanks a lot,

Title: Re: Script for calculating the effective mass in semi-conductors.
Post by: Anders Blom on September 22, 2012, 21:15

The script is general, but of course one has to adjust which band and which k-point you look at.

Title: Re: Script for calculating the effective mass in semi-conductors.
Post by: zegna on September 22, 2012, 23:14

Thanks for your reply,
I just found the information i was looking for,despite the fact i hadnt run the script due to time pressing as i will have to present my diploma at about one week,

so i searched around the site and it is a great site,i didnt have any idea of such rich and useful material!
But these things require enouph time for spend, so I ll come back soon to learn more

Title: Re: Script for calculating the effective mass in semi-conductors.
Post by: ams_nanolab on December 17, 2012, 09:31

Is it okay to run this analyzer for Extended Huckel calculations in other semiconductors?

Title: Re: Script for calculating the effective mass in semi-conductors.
Post by: Anders Blom on December 17, 2012, 12:32

Sure

QuantumATK Forum

QuantumATK => Scripts, Tutorials and Applications => Topic started by: Nordland on February 17, 2009, 00:14