Events in Physics
Tuesday, October 27, 2015
-Export as iCalendar |
Alix McCollamP5.23Tuning the carrier density and sub-band properties at the LaAlO3/SrTiO3 interface. Alix McCollam. High Field Magnet Laboratory, Radboud University Nijmegen, The Netherlands.
Oxides of transition metals have complex phase diagrams and a rich variety of ground states, where strong correlations between electrons mean that small adjustments of composition or structure can greatly change the properties of a system. Combining oxides in artificial heterostructures, by building up layers of atomically perfect thin films, provides the opportunity to engineer systems with specific functionalities. Moreover, heterostructures offer the possibility of properties at the interface which are not found in the bulk components. This approach was proven to be highly successful for III-V semiconductors, and is now showing signs of being equally fruitful for oxides, where a highly conducting 2-dimensional electron gas, which is also sometimes superconducting or magnetic, is found at interfaces between SrTiO3 and several other insulating perovskite oxides.
I will give a short introduction to the physics of oxide heterostructures and present the results of high field magnetotransport measurements on the LaAlO3/SrTiO3 system. Quantum oscillations observed in the resistivity and Hall effect allow us to probe the bandstructure of the interface electron gas, and give information about the properties of the mobile charge carriers. I will briefly discuss our current theoretical understanding of the interface electronic properties and how it relates to experiments, and will also present very recent measurements, in which we used the electric field effect to tune the carrier density of the electron gas and control the evolution of the conduction bandstructure and carrier properties.
References: A. McCollam et al., Quantum oscillations and subband properties of the two-dimensional electron gas at the LaAlO3/SrTiO3 interface. APL Materials 2, 022102 (2014). L. van Heeringen, et al., k.p subband structure of the LaAlO3/SrTiO3 interface. Phys. Rev. B {\bf 88}, 205140 (2013)
|