The spatial discretization of the single-cone Dirac Hamiltonian on
the surface of a topological insulator or superconductor needs a special
``staggered’’ grid, to avoid the appearance of a spurious second cone in
the Brillouin zone. We adapt the Stacey discretization from lattice
gauge theory to produce a generalized eigenvalue problem, of the form
\bm{\mathcal H}\bm{\psi}=\bm{E}\bm{\mathcal P}\bm{\psi}ℋ𝛙=𝐄𝒫𝛙,
with Hermitian tight-binding operators \bm{\mathcal H}ℋ,
\bm{\mathcal P}𝒫,
a locally conserved particle current, and preserved chiral and
symplectic symmetries. This permits the study of the spectral statistics
of Dirac fermions in each of the four symmetry classes A, AII, AIII, and
D.