The coupling relationships among the crystal structure, electronic structure, and physical properties of PrMn₂Ge₂ during its magnetic transition

Magnetic phase transitions govern the performance frontier of spintronic technologies, yet their microscopic origins in complex intermetallics remain elusive. Here, we resolve this challenge through a combined Physical Property Measurement System (PPMS), in situ X-ray diffraction (XRD), and Maximum Entropy Method (MEM) study of PrMn₂Ge₂, revealing that thermally driven electron transfer from Ge-4^p to Mn-3^d orbitals serves as the dominant mechanism for its sequential transitions: canted ferromagnetic (Fmc, 330 K) → conical magnetic order (Fmi_ab). Crucially, this directional charge migration first enhances Mn-Ge covalency, thereby driving lattice contraction; this amplified covalency subsequently strengthens Mn-Mn exchange interactions, inducing magnetic reorganization; finally, the resultant electron depletion at Pr sites weakens 4^f spin chirality, consequently suppressing topological transport. We thereby propose an electron-lattice-magnetism triple-coupling theory. Building directly on our discovery of electron-transfer-driven phase transitions, this framework establishes orbital-resolved electron dynamics as the central control mechanism-replacing thermal disorder-and enables two practical engineering strategies: Ge-site substitution to modulate charge transfer intensity, alongside epitaxial strain for precise control of magnetoelectric coupling via bond-length tuning. Collectively, this demonstrates electron-transfer engineering as a directly implementable strategy for manipulating topological states in functional magnets.