Enhancing magnetoresistance and mobility in Co3+xSn2-xS2 via non-stoichiometric doping for fermi level engineering

Precise tuning of the Fermi level in topological magnetic materials is essential for optimizing electronic properties, yet conventional doping methods often degrade structural integrity and magnetic order. Here, we achieve controlled electron doping in Co3Sn2S2 via non-stoichiometric substitution in Co3+xSn2-xS2 (0 ≤ x ≤ 0.3), preserving the Kagome lattice while enhancing transport properties. This method shifts the Fermi level upward close to the Weyl nodes, leading to a crossover from hole to electron conduction at 2 K. The x = 0.27 sample exhibits a giant transverse magnetoresistance (MR) of 1150% and ultra-high carrier mobility of 18,000 cm²V⁻¹s⁻¹, surpassing conventional magnetic Weyl semimetals. Our findings highlight the role of non-stoichiometric doping in optimizing topological electronic states, positioning Co3+xSn2-xS2 as a promising candidate for spintronic and quantum transport applications. Doping is an effective approach for tuning the Fermi level of topological magnetic materials, yet can degrade magnetic order. Here, controlled electron doping via non-stoichiometric substitution is achieved in Co3+xSn2-xS2, maintaining the Kagome lattice and enhancing transport behavior.