def find_lowest_point(slab):
    """
    This function is able to find the lowest point of the slab, it is used in slab_generator function.

    Parameters:

    Slab:
        ASE Atoms Object. The slab that we want.

    Return:
        A real number. Return the lowest point in the slab
    """
    lowest_height = 100000
    for atom in slab:
        if atom.position[2] < lowest_height:
            lowest_height = atom.position[2]
    return lowest_height
