Transition-metal oxides hold a wide range of potential applications in electronic devices owing to their fascinating properties, including ferroelectricity, superconductivity and Mott transitions. Among these oxides, perovskite vanadate of LaVO3 (LVO), better known as prototypical Mott-Hubbard insulator, has attracted growing research attention due to its unique magnetic phase transformation properties. Lately, a large number of researchers have focused on pursuing specific functional properties of LVO by regulating the magnetic and electronic phases of LVO by exploiting various external parameters like temperature, light irradiation, and stress field. These diverse external stimuli play a pivotal role in determining the electrical, structural and magnetic properties of LVO films.
One major challenge in elucidating the pure or intrinsic strain effect is how to effectively enable real-time, dynamic and in-situ control of the lattice strains of these thin films. This requires effective strategies for excluding the influence of various external parameters on the magnetic and electronic phases of the films. The most common approach for achieving this is by modifying their microstructures and associated physical properties by introducing electrically generated strain on the overlying films using piezoelectrically active Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT) single substrates.
Inspired by the pioneering studies, several functional thin films have been integrated onto the PMN-PT substrates. These films exhibit strain-mediated nonvolatile and reversible switching characteristics for magnetic, optical and electrical performances. Nevertheless, the intrinsic impacts of lattice strain on the nonvolatile electronic properties of LVO films are yet to be observed experimentally. In addition, the multifield combined control of the electronic properties in Mott-Oxide–Ferroelectric heterostructures remains sparsely explored despite its practical implication, especially in exploring the properties and extending the application of perovskite vanadates.
Herein, Professor Ming Zheng, Mr. Pengfei Guan, Dr. Xiang Ji and Professor Litong Guo from the China University of Mining and Technology experimentally investigated the combined optical and ferroelastic control in Mott insulating LVO films deposited on the PMN-PT substrates. In their approach, the reversible nonvolatile manipulation of the resistivity and strain states of the films was achieved by appropriately modifying the out-of-plane component of the substrate relative to the in-plane-polarization component. The strong photoresistivity and electroresistivity coupling effects were verified by combining the ferroelastic strain with the light stimulus. Their work is currently published in the journal, Physical Review Applied.
The research team demonstrated the conversion of the multiple resistivity states into nonvolatile and reversible evolution by adjusting the amplitude of the gate bias pulse and magnitude of the ferroelastic strain in the electrically triggered LVO/PMN-PT heterostructures. The voltage-actuated ferroelastic strain tunability of resistivity was effectively tuned by the light stimulus, and the resulting photoresistivity response could be enhanced by up to 65% through the generated ferroelasticity. Furthermore, the authors noted that the experimental results are useful for realizing a combined optical and ferroelastic control of the physical properties of various hybrid Mott-oxide–ferroelectric systems.
In a nutshell, the authors reported the successful voltage-triggered nonvolatile ferroelastic control of the electronic transport in LVO/PMN-PT structures. These findings showed the strong lattice-charge-orbital mediated coupling between the light-generated and ferroelastic-strain-induced effects. The correlated oxide-ferroelectric systems demonstrated in this study exhibit a range of potential applications. In a statement to Advances in Engineering, Professor Ming Zheng, the first and corresponding author said their findings would significantly contribute to the design and development of next-generation high-density nonvolatile electronic storage devices with additional vital functionality, like light-sensing capabilities, for various applications.
Zheng, M., Guan, P., Ji, X., & Guo, L. (2022). Combined Ferroelastic and Optical Control of Electronic Transport in Mott-Oxide–Ferroelectric Heterostructures. Physical Review Applied, 17(1), 014027-8.