A Quasi-1D Charge Density Wave in an Intercalated Magnetic Semiconductor

Layered van der Waals materials with an anisotropic in-plane structure offer a promising platform to study quasi-1D electron behavior as a function of charge doping. In this regard, the van der Waals semiconductor CrSBr is a material of particular interest. Its conduction band is nearly flat along Γ–X but dispersive along Γ–Y, leading to transport properties associated with weakly correlated 1D chains. However, the large concentration of bromine vacancies in exfoliated flakes typically limits the effects of electrical gating to the control of defect states, hindering the ability to study the properties of CrSBr when the Fermi energy is within the conduction band. Here, we overcome this limitation through chemical intercalation of CrSBr, which achieves a higher level of doping than is possible through electrical gating alone. Magnetization measurements of the intercalated material reveal a greatly enhanced magnetic ordering temperature and retention of the triaxial magnetic anisotropy of CrSBr. Further, scanning tunneling microscopy measurements reveal a quasi-1D charge density wave persisting to high temperature, highlighting that control of charge doping in CrSBr represents a route to access 1D electronic phases in van der Waals materials.