On Wednesday, 21 September 2016, Felix Trier succesfully defended his PhD thesis with the title “Quantum and field effects in oxide heterostructures”.
For the past three years Felix Trier has investigated the fascinating world of heterostructures where surprising things can happen when you put two materials together. For example, the interface between two ceramic materials can become metallically conducting even if both materials are insulating. And not only that, the interface can show novel quantum effects such as superconductivity, magnetism and the quantum Hall effect.
The oxide heterostructures are produced by pulsed laser deposition, where a powerful laser ablates a target which is then deposited on a substrate, creating atomically sharp interfaces. Felix developed a method for patterning the interface, making it possible to design microelectronic devices based on these systems. Ultimately, he hopes to use oxide heterostructures to create entirely new electronic components which can translate multiple inputs to multiple outputs, in contrast to conventional transistors where a single input is transformed to a single output.
Among the many notable results achieved during his Ph.D. study is the first observation of the quantum Hall effect in a heterostructure based on strontium titanate. The quantum Hall effect can only be observed in strong magnetic fields, and it manifests itself as a characteristic dependence of the resisitivity on the field strength. Felix could use the details of the field dependence to show that the interface conduction most likely takes place in ten parallel conducting subbands.
After finishing his PhD at DTU Energy, Felix will continue to work on oxide heterostructures in his new position as a postdoc at Unité Mixte de Physique CNRS/Thales near Paris, France.