Selective effects of selenium substitution on superconductivity and magnetic memory in 4Hb-TaS2
Disorder plays a central role in correlated quantum materials, but its effects can be highly selective when several electronic orders coexist. The van der Waals heterostructure 4Hb-TaS2 provides such a case, combining superconductivity, charge-order tendencies, strong scattering, and magnetic memory manifested through spontaneous vortices. Here we use Se substitution as a controlled local perturbation of the disorder landscape in 4Hb-TaS2. We find that superconductivity remains remarkably robust while the magnetic memory is strongly suppressed at higher Se concentrations. These results show that Se substitution does not create the hidden magnetic memory, but instead selectively weakens its macroscopic manifestation. More broadly, they reveal a sharp separation between robust superconducting and hidden-memory phases, and a highly disorder-sensitive spontaneous-vortex response in 4Hb-TaS2.