  Magnetic materials with noncollinear spin textures are promising for
spintronic applications. To realize practical devices, control over the length
and energy scales of such spin textures is imperative. The chiral helimagnets
Cr1/3NbS2 and Cr1/3TaS2 exhibit analogous magnetic phase diagrams with
different real-space periodicities and field dependence, positioning them as
model systems for studying the relative strengths of the microscopic mechanisms
giving rise to exotic spin textures. Here, we carry out a comparative study of
the electronic structures of Cr1/3NbS2 and Cr1/3TaS2 using angle-resolved
photoemission spectroscopy and density functional theory. We show that bands in
Cr1/3TaS2 are more dispersive than their counterparts in Cr1/3NbS2 and connect
this result to bonding and orbital overlap in these materials. We also
unambiguously distinguish exchange splitting from surface termination effects
by studying the dependence of their photoemission spectra on polarization,
temperature, and beam size. We find strong evidence that hybridization between
intercalant and host lattice electronic states mediates the magnetic exchange
interactions in these materials, suggesting that band engineering is a route
toward tuning their spin textures. Overall, these results underscore how the
modular nature of intercalated transition metal dichalcogenides translates
variation in composition and electronic structure to complex magnetism.
