Messages

1

General Questions and Answers / Re: InAs bulk bandstructure

« on: October 7, 2015, 10:53 »

Hi Anders, thank you for the explanation. Jan

2

General Questions and Answers / InAs bulk bandstructure

« on: October 6, 2015, 14:00 »

I followed the tutorial for the InAs bandstructure MGGA calculation, but it results in zero bandgap. Where is my fault? Thanks

3

General Questions and Answers / Re: VNL segmentation fault on Ubuntu

« on: October 31, 2012, 11:46 »

Thanks, I´ll try it. (sorry for additional pers. message) Jan

4

General Questions and Answers / VNL segmentation fault on Ubuntu

« on: October 31, 2012, 11:02 »

Hi, after installing vnl 12.2.2, the segmentation fault appears after adding new structure in builder:

QGLShader::link: "Fragment shader(s) linked, vertex shader(s) linked.
 "
Segmentation fault

I am runing under Ubuntu 9.10

Thaks for any help

5

Installation and License Questions / Re: Parallel calculations using ATK 10.8.2

« on: January 28, 2011, 11:53 »

Thanks Anders, I did not find this manual.

Jan

6

Installation and License Questions / Parallel calculations using ATK 10.8.2

« on: January 27, 2011, 15:04 »

There exists any manual for parallel calculations using ATK 10.8.2 similar to manual for 2008.10 version? Are they any changes? Should I run atkpython instead of atk by testing using mpiexec?
I have problem Lamnodes Failed during mpiexec start.
Thanks for any help
Jan

7

General Questions and Answers / Re: SE pseudopotentials (InSb)

« on: December 14, 2009, 12:15 »

or from:

Phys. Rev. B 57, 6493–6507
Empirical spds* tight-binding calculation for cubic semiconductors: General method and material parameters

8

General Questions and Answers / Re: SE pseudopotentials (InSb)

« on: December 14, 2009, 12:11 »

Could be possible to include parameters for InSb from:

Yajun Wei and Manijeh Razeghi
Modeling of type-II InAs/GaSb superlattices using an empirical tight-binding method
and interface engineering
PHYSICAL REVIEW B 69, 085316 (2004)

?

9

General Questions and Answers / SE pseudopotentials (InSb)

« on: December 11, 2009, 14:13 »

Hi,
I tried different pseudopotential sets for fcc InSb crystal in ATK SE. All results show huge value of the bandgap (several eV). I appreciate any recommendation.

Jan

10

Installation and License Questions / license file for ATK SE

« on: November 3, 2009, 13:08 »

Hi Anders,
I try to install ATK SE under UBUNTU 9.04. I am not sure about the license file - need I to fill the trial version form for it, or will it be generated automaticaly till end of this year?

I have done this step:

Setting up machine for stand-alone license system:
 Success[0] -  System initialization successfully done.

Thanks for help

Jan

11

Scripts, Tutorials and Applications / Re: Script for calculating the effective mass in semi-conductors.

« on: June 17, 2009, 10:04 »

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

12

Scripts, Tutorials and Applications / Re: Script for calculating the effective mass in semi-conductors.

« 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

13

Scripts, Tutorials and Applications / Re: Script for calculating the effective mass in semi-conductors.

« 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

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):

----------------------------------------------------------------------
# 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

14

Scripts, Tutorials and Applications / Re: Script for calculate the bandgap.

« on: February 16, 2009, 13:58 »

Hey, thats sounds good. Holes are important for me!

Jan

15

Scripts, Tutorials and Applications / Re: Script for calculate the bandgap.

« on: February 16, 2009, 13:43 »

Thanks for the valuable reference. My idea was to calculate the eff. masses for the strained layer from the bandstructure. The DFT will not be the best solution, I am afraid.

Jan