[Wien] FSGEN

Andrew Smith Andrew.Smith at spme.monash.edu.au
Thu Aug 14 01:41:51 CEST 2003


Hi Shen 

A few comments that I hope will get you going further.

(1)  Explanation: What you are doing is to run a band structure
calculation for many points on a k space plane to produce the
corresponding energy values (eigenvalue). You then have to use your
graphics software to produce a contour plot (only zero value for the
Fermi surface). What this means is that you have to be sure that you
include all of the bands that contain all occurrences of (close to)the
value zero (which band you have is given by the band index at the
beginning of the block in the output file; and the energy value is the
eigenvalue).

(2) vk(1,jk),vk(2,jk),vk(3,jk),xval(jk),eigen(je,jk)  
These are respectively: the 3 co-ordinates of the  k vector, the modulus
of the k vector and the energy eigenvalue 

What is the meaning of negative vkz? 
I suppose you mean for example -56.88422 (first row) 
You are looking at the wrong column.
-56.88422 This is the negative value of eigen(je,jk).

(It is negative with a large modulus, because the band index counting
starts for the bottom and goes up - for the fermi surface you need to be
looking for (close to) zeros. That is for much higher band indices).

Hope that this can get you started

Andrew Smith

Shen Li Qiu wrote:
> 
> Dear All,
>  I still have some questions about FSGEN. Take TiC as an example. I choose
> the plane Gamma-X-XP-K-Gamma and 40 points in both kx and ky directions.
> 
> (1) UG says (page 128) "Run spaghetti with input-options such that it
> prints the bands which intersect EF to case.spaghetti.ene (line 6, see
> section.8.3). I followed the instruction in sec. 8.3 and 7.5 but it doesn't
> make any chnage in case.spaghetti.ene. What input-options should be used?
> 
> (2) According to spag.f and get_k.f the values of each row in
> case.spaghetti.ene are vk(1,jk),vk(2,jk),vk(3,jk),xval(jk),eigen(je,jk) and
> vk1=vkx, vk2=vky, vk3=vkz. The data of bandindex 1 in cTiC.spaghetti.ene
> are attached at the end of this email.
> What is the meaning of negative vkz? What is the physicsl meaning of xval?
> 
> (3) Dr. Blaha metioned in his email of 7/29/03 that "You can find it
> (x-len, y-len) either from one of the vk-components or from the distance
> from the 'beginning' in the 4th column......First follow from Gamma to the
> end of the first line (x-direction), then look more at the end, when x is
> back at the "zeroth" value, but y is at a maximum".
>  From the attached data how to see that "x is back at the 'zeroth' value,
> but y is at a maximum". The value of xval in colum 4 changes monotonously,
> how to determine x-len and y-len "from the distance from the 'beginning' in
> the 4th column"? I'm missing something here, please let me know. I'd like
> to know how to get x-len and y-len correctly.
> 
> (4) Please give me some references on FS calculations using WIEN2k.
> 
> Thanks in advance.
> 
> Shen Li Qiu
> 
>  bandindex:           1
>    0.00000   0.00000   0.00000   0.00000 -56.88422
>    0.06202   0.06202  -0.06202   0.10741 -56.88063
>    0.12404   0.12404  -0.12404   0.21484 -56.87168
>    0.18605   0.18605  -0.18605   0.32225 -56.85943
>    0.24807   0.24807  -0.24807   0.42967 -56.84720
>    0.31009   0.31009  -0.31009   0.53709 -56.83783
>    0.37211   0.37211  -0.37211   0.64451 -56.83446
>    0.12404   0.00000   0.00000   1.71864 -56.87950
>    0.18605   0.06202  -0.06202   1.82605 -56.87247
>    0.24807   0.12404  -0.12404   1.93347 -56.86136
>    0.31009   0.18605  -0.18605   2.04089 -56.84905
>    0.37211   0.24807  -0.24807   2.14830 -56.83906
>    0.43412   0.31009  -0.31009   2.25573 -56.83379
>    0.49614   0.37211  -0.37211   2.36314 -56.83491
>    0.55816   0.43412  -0.43412   2.47056 -56.84193
>    0.62017   0.49614  -0.49614   2.57798 -56.85324
>    0.68220   0.55816  -0.55816   2.68540 -56.86538
>    0.74421   0.62017  -0.62017   2.79281 -56.87543
>    0.24807   0.00000   0.00000   3.86694 -56.86768
>    0.31009   0.06202  -0.06202   3.97436 -56.85854
>    0.37211   0.12404  -0.12404   4.08178 -56.84759
>    0.43412   0.18605  -0.18605   4.18920 -56.83750
>    0.49614   0.24807  -0.24807   4.29661 -56.83111
>    0.55816   0.31009  -0.31009   4.40403 -56.83044
>    0.62017   0.37211  -0.37211   4.51145 -56.83518
>    0.68220   0.43412  -0.43412   4.61887 -56.84439
>    0.74421   0.49614  -0.49614   4.72629 -56.85548
>    0.37211   0.00000   0.00000   5.80042 -56.85189
>    0.43412   0.06202  -0.06202   5.90783 -56.84267
>    0.49614   0.12404  -0.12404   6.01526 -56.83382
>    0.55816   0.18605  -0.18605   6.12267 -56.82755
>    0.62017   0.24807  -0.24807   6.23009 -56.82570
>    0.68220   0.31009  -0.31009   6.33751 -56.82846
>    0.74421   0.37211  -0.37211   6.44493 -56.83547
>    0.49614   0.00000   0.00000   7.51906 -56.83603
>    0.55816   0.06202  -0.06202   7.62647 -56.82911
>    0.62017   0.12404  -0.12404   7.73389 -56.82390
>    0.68220   0.18605  -0.18605   7.84131 -56.82206
>    0.74421   0.24807  -0.24807   7.94872 -56.82357
>    0.62017   0.00000   0.00000   9.02286 -56.82451
>    0.68220   0.06202  -0.06202   9.13028 -56.82124
>    0.74421   0.12404  -0.12404   9.23770 -56.82037
>    0.74421   0.00000   0.00000   9.41311 -56.82015
>    0.24807   0.12404   0.00000  10.48725 -56.86448
>    0.31009   0.18605  -0.06202  10.59466 -56.85338
>    0.37211   0.24807  -0.12404  10.70208 -56.84220
>    0.43412   0.31009  -0.18605  10.80950 -56.83394
>    0.49614   0.37211  -0.24807  10.91692 -56.83098
>    0.37211   0.12404   0.00000  11.99105 -56.84945
>    0.43412   0.18605  -0.06202  12.09846 -56.83947
>    0.49614   0.24807  -0.12404  12.20588 -56.83132
>    0.55816   0.31009  -0.18605  12.31330 -56.82734
>    0.62017   0.37211  -0.24807  12.42071 -56.82848
>    0.68220   0.43412  -0.31009  12.52814 -56.83418
>    0.74421   0.49614  -0.37211  12.63555 -56.84340
>    0.49614   0.12404   0.00000  13.70969 -56.83488
>    0.55816   0.18605  -0.06202  13.81710 -56.82778
>    0.62017   0.24807  -0.12404  13.92452 -56.82373
>    0.68220   0.31009  -0.18605  14.03194 -56.82359
>    0.74421   0.37211  -0.24807  14.13935 -56.82747
>    0.62017   0.12404   0.00000  15.21349 -56.82414
>    0.68220   0.18605  -0.06202  15.32090 -56.82115
>    0.74421   0.24807  -0.12404  15.42832 -56.82093
>    0.74421   0.12404   0.00000  15.60373 -56.82017
>    0.49614   0.24807   0.00000  15.88108 -56.83144
>    0.55816   0.31009  -0.06202  15.98850 -56.82565
>    0.62017   0.37211  -0.12404  16.09591 -56.82351
>    0.62017   0.24807   0.00000  16.27133 -56.82304
>    0.68220   0.31009  -0.06202  16.37875 -56.82074
>    0.74421   0.37211  -0.12404  16.48617 -56.82177
>    0.74421   0.24807   0.00000  16.66158 -56.81994
>    0.74421   0.37211   0.00000  16.78562 -56.81961
> 
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-- 
 
--------------------------------------
andrew.e.smith at spme.monash.edu.au

Dr. Andrew E. Smith
School of Physics & Materials Engineering
P.O. Box 27
Monash University
Victoria 3800
Australia

Direct  + 61 3 9905 3699
Fax     + 61 3 9905 3637



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