Redox Controllable Switch of Crystalline Phase and Physical Property in SrVO_x Epitaxial Films

Transition-metal oxides have attracted much attention due to its abundant crystalline phases and intriguing physical properties. However, some of these compounds are difficult to be fabricated directly in film form due to the ease of valence variation of transition-metal elements. In this work, we reveal the reversible structural transition between SrVO_3 and Sr_2V_2O_7 films via thermal treatment in oxygen atmosphere or in vacuum. Based on this, Sr_2V_2O_7 epitaxial films are successfully synthesized and studied. Property characterizations show that the semitransparent and metallic SrVO_3 could reversibly switch into transparent and insulating Sr_2V_2O_7, implying potential applications in controllable electronic and optical devices.