Problem in legth of ky and kz in 2D fermisurface

[SubeenLim]

Dear Developer,

For studying topological material, I often try to calculate 2D fermi surface. Fermisurfer is so useful in this situation.
I have some question.
I calculated the Fermi surface by creating a slab structure in the [100] direction. I am comparing the 2D Fermi surface of this slab structure with the [100] 2D Fermi surface in the bulk structure.

As shown in the figure below, the bz_line.dat is drawn, with the top image representing the calculation results of the slab and the bottom image showing the calculation results of the bulk structure.

First question: Does the bz_line.dat drawn in the slab results represents the bulk 2D BZ?
Second question: If so, why do the ky ranges differ between the bulk calculation results and the 2D bulk BZ results from the slab calculations? (The kz range matches perfectly in both figures.)

Below, I have attached pictures for better understanding.

Could you help identify what the problem is?
Thanks,
Best,
SB

[mitsuaki1987]

I think it is better to check the supercell structure.
I doubt whether it is really what you plan to compute.