Valence Manipulation
The reductive intercalation of chemically diverse systems with alkali metals has demonstrated that a spectacular transformation of the electronic ground state, from a magnetic insulator to a metal or superconductor, is possible on certain occasions. Valence manipulation by topotactic insertion methods can lead to chemical compounds displaying novel physical behaviour. The interplay of structural and electronic properties finds important examples among solids with topologies ranging from zero- (0D) to three- (3D) dimensional lattices. Their capacity for multifunctional capability depends on the host lattice's potential to experience variable perturbations with respect to its crystal chemistry and its electronic properties. We combine the effects of "intrinsic" chemical pressure induced by cation/anion substitution against "extrinsic" parameters such as the applied hydrostatic pressure on the parent (undoped) compound. This allows shifting the phase boundary between localised/magnetic and itinerant behaviour through the control of the on-site Coulomb repulsion (U) and bandwidth (W) in strongly correlated electron systems.
Chemical model: LixMo2SbS2.