Correlation Length as a Function of Mo Composition and Temperature*

VO₂ undergoes a metal-to-insulator transition at 340 K, during which a structural transition from rutile (R) to monoclinic (M1) also occurs. The origins of these transitions are not well understood. Doped VO₂ has been studied in efforts to tune the transition temperature and understand the origin of these transitions. However, there are discrepancies in the phase diagrams of these systems. One such example is V_1-x Mo_xO₂. Previous single-crystal diffuse scattering studies found the existence of a 2D-M2 phase between 0.19 ≤ x ≤ 0.43. Here, a systematic study of correlation length as a function of both Mo concentration and temperature is presented to better understand the origins of these structural phase transitions.