Connecting the dots: Time-reversal symmetric Weyl semimetals with tunable Fermi arcs

We propose a one-parameter family of noninteracting lattice models for Weyl semimetals with four Weyl nodes and tunable Fermi arcs. These two-band model Hamiltonians are time-reversal symmetric with ${\mathrm{T}}²=+1$, and tuning the parameter changes the connectivity of the Fermi arcs continuously without affecting the location and chiralities of the Weyl nodes in the bulk Brillouin zone. The bulk polarization and magnetization are shown to vary with this parameter, a dependence inaccessible to the low energy effective field theory.