Electric Field Control of Metal-Insulator Transition in Charge-Ordered Fe2BO4

The structure and electric properties of single-crystal Fe2BO4 are measured by in situ high-resolution X-ray diffraction combined with current-voltage (I-V) measurements. A superstructure due to charge ordering (CO) is found at room temperature, and the superstructure peak disappears when the applied electric field exceeds a certain threshold. I-V characteristics show a sharp resistance drop, indicating a metal-insulator transition (MIT) induced by applied voltage and revealing electron-lattice coupling, which is due to the Joule heating effect. Moreover, the Fe2BO4 single crystal exhibits a multidomain monoclinic phase in its original state, which transforms into a single-domain orthorhombic phase when a voltage of 200 V is applied. MIT, CO state collapse, and structural phase change have been observed simultaneously and indicate that the CO structural phase change can be controlled by an electric field.