Inhomogeneous electronic states associated with charge-orbital order/disorder in BaV10O15 probed by photoemission spectromicroscopy

We have performed scanning photoemission spectromicroscopy of BaV₁₀O₁₅ across the metal-insulator transition at 123 K, which is accompanied by V 3d charge/orbital order and V trimerization. Nucleation of metallic domains is observed at the cleaved surface of BaV₁₀O₁₅ single crystals, similar to Cr-doped V₂O₃ in which electronic configurations of Cr³⁺ and V³⁺ are the same as those of V²⁺ and V³⁺ in BaV₁₀O₁₅. Typical domain size is ~5-10 μm at 150 K, just above the transition temperature. The metallic domains continuously grow up to 240 K, well above the transition temperature. The temperature evolution of the metallic phase in BaV₁₀O₁₅ is different from that of Cr-doped V₂O₃, probably due to the charge degrees of freedom in BaV₁₀O₁₅