All are cordially invited to attend the colloquium for the Department of Physics and Astronomy’s faculty search candidate, Dr. Anderson Janotti. Dr. Janotti will give the talk “Two-dimensional Electron Gases at Complex Oxide Interfaces” on Tuesday, February 17, at 4:10 p.m. in Webster room 17. See the abstract below for more details.
Please meet our candidate and share in refreshments, 3:45-4:10 p.m. in the foyer on floor G above the lecture hall.
Abstract:
Complex oxides are fascinating materials that host an array of phenomena, from which high-Tc superconductivity, colossal magnetoresistance, magnetism, and ferroelectricity are just a few examples. Recent advances in epitaxial growth have led to heterostructures of complex oxides with structural quality that rivals that of conventional semiconductors, revealing exotic properties that are absent in the building block compounds. For example, a two-dimensional electron gas (2DEG) was created at the interface between two normally insulating oxides—SrTiO3/LaAlO3, or between SrTiO3 and a Mott insulator such as GdTiO3. In the case of SrTiO3/GdTiO3, the electron density is an order of magnitude higher than those obtained using conventional semiconductors, sparking the interest in novel device applications. Superconductivity and ferromagnetism have already been reported. In spite of almost a decade of research, the origin of the excess charge at the interface and the mechanisms that determine the density of the 2DEG are still controversial, and fundamental properties of this interfacial metallic state are not fully understood. In this presentation we will discuss how first-principles calculations can provide insights into the origin and nature of the 2DEG. We will report on electron correlation effects and how the electronic structure of these heterostructures can be drastically altered, turning from metallic into insulating, by changing the thickness of the SrTiO3 layer. Finally, we address the potential of oxide heterostructures for future electronic devices, and discuss some design principles.
