Pressure‐induced Mott transition in transition‐metal iodides (invited)

Many of the transition‐metal (TM) compounds, because of exchange and correlation interactions within the narrow and poorly overlapping d bands, become antiferromagnetic insulators, the Mott insulators (MI). The properties of the MI and their gradual transition into the noncorrelated metallic state (the Mott transition) are of crucial importance for the elucidation of high‐temperature superconducting materials features in particular and to magnetism in general. The transition of the MI into a metal can be achieved either by doping or by high pressure. The first method is definitely inappropriate for studying the nature of the Mott transition; for the narrow‐band materials the electronic and structural disorder inherent in doping has a strongly perturbing effect. To yield the definitive data on the Mott transition, high‐pressure work on well‐characterized materials should be sought. The present studies provide for the first time extensive information on the Mott–Hubbard gap closure induced by high pressure....