The nature of phase transitions in strongly correlated systems remains a longstanding puzzle. Using advanced Mueller matrix ellipsometry and effective medium approximation, this study uncovers the microscopic behavior of phase transitions in α-(BEDT-TTF)2I3 and its substituted salts. The results confirm the first-order nature of the transition, quantify phase coexistence, and reveal fundamental differences in transition mechanisms. This work offers a powerful approach to exploring the complex nature of phase transitions in correlated electron systems.
doi.org/10.1103/PhysRevB.111.195142
