Comparative Electronic Structures of the Chiral Helimagnets Cr1/3NbS2 and Cr1/3TaS2

Magnetic materials with noncollinear spin textures arepromisingfor spintronic applications. To realize practical devices, controlover the length and energy scales of such spin textures is imperative.The chiral helimagnets Cr1/3NbS2 and Cr1/3TaS2 exhibit analogous magnetic-phase diagramswith different real-space periodicities and field dependence, positioningthem as model systems for studying the relative strengths of the microscopicmechanisms giving rise to exotic spin textures. Although the electronicstructure of the Nb analogue has been experimentally investigated,the Ta analogue has received far less attention. Here, we presenta comprehensive suite of electronic structure studies on both Cr1/3NbS2 and Cr1/3TaS2 usingangle-resolved photoemission spectroscopy and density functional theory.We show that bands in Cr1/3TaS2 are more dispersivethan their counterparts in Cr1/3NbS2, resultingin markedly different Fermi wavevectors. The fact that their qualitativemagnetic phase diagrams are nevertheless identical shows that hybridizationbetween the intercalant and host lattice mediates the magnetic exchangeinteractions in both of these materials. We ultimately find that ferromagneticcoupling is stronger in Cr1/3TaS2, but largerspin-orbit coupling (and a stronger Dzyaloshinskii-Moriyainteraction) from the heavier host lattice ultimately gives rise toshorter spin textures.