Colloquium spekaer, Anderson Janotti (University of Delawre) today at 3:45pm

[Patterson, Robin L.]

Please join us for the Physics Colloquium today, at 3:45 PM in The Robert Smith Seminar Room. There will be a reception at 3:30PM in the Atrium. Details concerning the talk are as follows:

Speaker:         Anderson Janotti (University of Delaware)
Date:             Tuesday, February 27, 2018
Time:             3:45PM
Place:            1080 Physics Research Building, The Robert Smith Seminar Room
Title:              Vacancies, Small Polarons and Two-dimensional Electron Gases in Complexes Oxides



Abstract:   Progress in epitaxial growth of complex oxides have led to heterostructures with a unique set of physical phenomena, such as the formation of a high-density two-dimensional electron gas (2DEG) at the interface between two normally insulating materials-e.g. SrTiO3/LaAlO3 and SrTiO3/GdTiO3. Superconductivity and magnetic ordering have been demonstrated in these systems, sparking the interest in novel device applications. The formation of a 2DEG at the interface between SrTiO3 and Mott insulators, such as GdTiO3, have also been demonstrated, with electron densities that are over an order of magnitude higher than those realized with conventional semiconductors. Charge transport in these systems exhibit exquisite behavior, varying drastically from metal to insulator depending on the thickness of the building-block layers. Despite the intense research efforts in the last decade, the origin of the excess charge and the mechanisms that determine the density of the 2DEG are still under debate, and fundamental properties of the 2DEG are not fully understood. In this presentation, we will discuss how computer simulations can provide insights into the origin and nature of the 2DEG. Based on results of first-principles calculations we will discuss electron correlation effects and how the electronic structure of these heterostructures can be drastically altered, turning from metallic into insulating, through charge localization in ultrathin layers. Charge localization will also be addressed in the context of small polaron formation, and these concepts will be used to explain transport and optical phenomena observed in the bulk materials.
The website for the colloquium is https://physics.osu.edu/physics-colloquium-schedule


Also, there is the speaker student discussion starting just after the colloquium, at 4:45pm in the Smith Seminar Room.



Robin
[The Ohio State University]
Robin Patterson
Program Coordinator
Department of Physics
1040K Physics Research Building, 191 W. Woodruff Avenue, Columbus, OH 43210
(614) 292-8523 Office     (614) 292-7557 Fax
patterson.716 at osu.edu<mailto:patterson.716 at osu.edu> osu.edu<http://osu.edu/>

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