Exploring Spin-Orbit Coupling and Correlated Phenomena in Iridate-Based Ferroelectric Transistors and Tunnel Junctions

University Of Nebraska-Lincoln, Lincoln NE

Investigators

Abstract

Non-Technical Abstract: In heavy transition metal oxides such as iridates, the electron spin is strongly coupled with its orbital motion. This effect, when competing with other interactions involving the charge and structural order, can significantly alter the material's electronic and magnetic properties. This research project explores two material strategies to understand, control and enhance these couplings in iridate-based composite materials. The gained knowledge can be utilized to design novel nanoscale devices that transcend the performance limits of the current information technology. The research provides exciting research opportunities for students at the graduate, undergraduate and high school levels, exposing the students to cutting-edge nanoscience and materials research. The integrated outreach components aim at promoting the K-12 STEM education and disseminating science to the general public. The efforts include creating a web-based comic story centered around a teenage girl learning the related device concept and its application in modern electronic technology, and contributing a post on the related topic to the Funsize Physics website. Technical Abstract: The goal of this research project is to probe and control the spin-orbit coupling and correlation-driven phenomena in epitaxial thin films of the 5d transition metal oxides SrIrO3 and Sr2IrO4 using two prototype device structures, the ferroelectric field effect transistors and the ferroelectric tunnel junctions. The research activities include examining the individual roles of carrier density, lattice strain, and defects in the spin transport of SrIrO3, modulating the magnetic anisotropy in Sr2IrO4, searching for carrier density-driven metal-insulator and magnetic phase transitions, and exploring the tunneling characteristics of iridate-based tunnel junctions. This research involves advanced epitaxial deposition of complex oxide heterostructures, nanoscale device fabrication, scanning probe microscopy, variable temperature magnetotransport and tunneling spectroscopy studies. The proposed efforts stand to advance the fundamental understanding of spin-orbit coupling and its competition with various correlated energies in the heavy transition metal oxides. The gained knowledge can be leveraged to develop novel oxide-based nonvolatile or multifunctional electronic and spintronic applications.