Seminar: Graduate Seminar
Harnessing Oxide Functionality Towards Novel Electronic Devices
| Mott materials hold considerable promise for advanced technologies, including electrochemical, electronic, magnetic, and optoelectronic devices. Over the past decades, they have gained attention owing to their metal to insulating electronic phase transition, suggesting sharp subthreshold swing characteristics. However, their advancement towards electronic devices has been impeded by several major challenges, including a comprehensive understanding of their underlying physics and the enhancement of film quality and interfacial properties.
In this study, we present our advancement towards a successful prototype of a field effect device based on a Mott material system, which exhibits unique filling-control behavior via reversible gate control. We start by establishing a scalable, high-quality, and epitaxial thin film growth using the industry-compatible oxide molecular beam epitaxy. Subsequently, through the application of small biaxial mechanical stress, we illustrate how it is possible to drive a metallic system towards its Mott insulating state, driven by concurrent symmetry breaking and variations in orbital overlap. Furthermore, we highlight the profound impact of surface inhomogeneity by revealing significant disparities between two modes of x-ray absorption spectroscopy acquisition—one surface-sensitive and the other probing the entire film thickness. Finally, after maturing a photolithography-based fabrication process, we introduce an electrostatic modification approach utilizing a back gate, revealing intriguing behavior in carrier concentration modulation. Notably, despite electrons being the primary carriers, the observed increase in electric resistance with rising carrier concentration underscores the filling-control phenomenon inherent to Mott materials. These findings signify the advancement towards harnessing the potential of Mott materials for novel functional devices. Ph.D. Under the supervision of Prof. Lior Kornblum.
|