[Wannier] Question on " Unable to satisfy B1 with any of the first 12 shells"

[Jonathan Yates]

Dear Houchen,

 Your unit cell has a long a_2 cell vector, and you are sampling the BZ very finely in this direction. This means that the k-points in this direction are very very close together. So the early shells of k-point are mostly in that direction. In fact we have to go out to the 578th k-point shell to find k-point corresponding to the a_3 direction.
 You might want to consider if this k-point sampling is necessary for this system.

So to make your calculation “run” the only default parameter you need to change is to set
 Search_shells=600
Note that if you set iprint=3 in the output file you will get more information on the search for the b vectors, which is useful for understanding issues such as this.

 I have copied the output of W90 using  Search_shells=600 below

Yours
  Jonathan




 +----------------------------------------------------------------------------+
 |                        Shell   # Nearest-Neighbours                        |
 |                        -----   --------------------                        |
 |                          1               2                                 |
 |                          3               2                                 |
 |                          4               2                                 |
 |                        578               2                                 |
 |                        579               2                                 |
 |                        586               2                                 |
 +----------------------------------------------------------------------------+
 | Completeness relation is fully satisfied [Eq. (B1), PRB 56, 12847 (1997)]  |
 +----------------------------------------------------------------------------+
 |                  b_k Vectors (Ang^-1) and Weights (Ang^2)                  |
 |                  ----------------------------------------                  |
 |            No.         b_k(x)      b_k(y)      b_k(z)        w_b           |
 |            ---        --------------------------------     --------        |
 |             1         0.000000    0.027886   -0.002218   637.399983        |
 |             2         0.000000   -0.027886    0.002218   637.399983        |
 |             3         0.074481   -0.001091   -0.019598    82.840923        |
 |             4        -0.074481    0.001091    0.019598    82.840923        |
 |             5         0.074481   -0.028977   -0.017380     1.416631        |
 |             6        -0.074481    0.028977    0.017380     1.416631        |
 |             7         0.223442    0.080384    0.856883     0.330359        |
 |             8        -0.223442   -0.080384   -0.856883     0.330359        |
 |             9         0.223442    0.052499    0.859101     0.276083        |
 |            10        -0.223442   -0.052499   -0.859101     0.276083        |
 |            11         0.297922    0.079294    0.837285     0.026087        |
 |            12        -0.297922   -0.079294   -0.837285     0.026087        |
 +----------------------------------------------------------------------------+
 |                           b_k Directions (Ang^-1)                          |
 |                           -----------------------                          |
 |            No.           x           y           z                         |
 |            ---        --------------------------------                     |
 |             1         0.000000    0.027886   -0.002218                     |
 |             2         0.074481   -0.001091   -0.019598                     |
 |             3         0.074481   -0.028977   -0.017380                     |
 |             4         0.223442    0.080384    0.856883                     |
 |             5         0.223442    0.052499    0.859101                     |
 |             6         0.297922    0.079294    0.837285                     |
 +----------------------------------------------------------------------------+


> On 11 Oct 2020, at 11:29, Li, Houchen <houchenli at fas.harvard.edu> wrote:
> 
> Dear all,
> 
> I am trying to use VASP&wannier90 to calculate monolayer beta-RhBi2 band structure.
> Then I have the problem with "unable to satisfy Bi with any of xx shells" error. While the bulk band structure works well.
> 
> I looked for possible solutions, and I have tried to change the parameter "k_mesh_tol" and "search_shell" both to much bigger values. It still does not work.
> 
> Some related codes are attached. Many thanks for potential solutions.
> 
> Houchen
> 
> 
> <RhBI2.zip>_______________________________________________
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