Events Calendar

Band-Engineered Complex Oxide Interfaces: New Insights and Opportunities

Speaker: Professor Bharat Jalan, University of Minnesota

Talk Title: Band-Engineered Complex Oxide Interfaces: New Insights and Opportunities

Series: Graduate Seminar

Abstract: Complex oxide heterostructures can show strong correlation effects, novel magnetism, high breakdown voltage, and high 2D electron density (of the order of 1014 cm-2), unattainable in traditional semiconductor heterostructures. High 2D electron densities are of particular interest for studying low-dimensional physics in narrow d-band materials, in addition to fabricating novel plasmonic field-effect devices (FETs). Recent advances in thin film growth approaches have enabled the growth of this material class in thin film and heterostructure forms with pristine structural quality (similar to that of the conventional semiconductors). However the grand challenge in the field is to obtain these materials with the high level of stoichiometric and defect control. In this talk, I will present my groups effort to address these challenges and to utilize intrinsic defects as a new degree of freedom to control materials electronic and magnetic property using the hybrid molecular beam epitaxy (MBE) approach. In particular, I will discuss the role of intrinsic defects in realizing and tailoring the 2D electron gas at perovskite oxide heterojunctions.

I will then present a novel approach for creating high-density 2DEGs at perovskite heterojunction using internal charge transfer. 2D carrier density much higher density than expected based on resolution of the polar discontinuity at perovskite oxide heterojunctions can be achieved via internal charge transfer using band-engineered interfaces. Combining DFT modeling and experiments using x-ray photoelectron spectroscopy, scanning transmission electron microscopy, electron energy loss spectroscopy, energy dispersive x-ray spectroscopy and electronic transport measurements, I will discuss the origin of these carriers, dimensionality and transport mechanisms. Finally, I will discuss how electron and hole doping via band-engineered approaches can be achieved, which may provide an exceptional route to revisit the electronic phase diagrams of transition metal oxides in the clean doping limit.

This work is supported through the University of Minnesota MRSEC under awards DMR-1420013.


Host: Professor Jayakanth Ravichandran

Location: James H. Zumberge Hall Of Science (ZHS) - 159

Audiences: Everyone Is Invited

Contact: Martin Olekszyk