Franz Herling- ESR 12, June 2018 - May 2021
NanoGUNE, San Sebastián, Spain
Master thesis:
"Spin-orbit interaction in InAs/GaSb heterostructures quantified by weak antilocalization. I studied the 2D topological insulator InAs/GaSb. The double quantum wells were grown by molecular beam epitaxy and patterned by standard photolithography. My task was to electrical characterize the nanostructures at low temperatures and high magnetic field in He cryostats."Humboldt University, Berlin (Germany)
Personal Training Committee
Main Supervisor: Felix Casanova, NanoGUNE
Co-supervisor: Edmund Linfield, LEEDS
Mentor: Axel Rudzinski, RAITH
Planned secondments
At RAITH, Germany (December 2018) for Training in pattern fidelity by means of Proximity Effect Correction including experimental scattering, parameter evaluation and dosage factor adjustment,
At LEEDS, United Kingdom (April 2019) on the growth of high-quality metallic alloys by co-sputtering,
At Chalmers, Sweden (March 2020) on low temperature cryogenics & electronic measurements.
At GRA SEMI, Spain (August 2020) on growth of 2D materials and assembly of van der Waals heterostructure.
PhD Project
Spin-to-charge conversion and spin manipulation in strong spin-orbit coupling systems
Objectives: An ultimate goal of spintronics is to be able to create and manipulate spin currents without the need of any ferromagnetic materials and in this context the spin Hall Effect (SHE), which transforms an electrical current into a spin current, has been the main mechanism to be studied. Novel spin-orbit coupling related effects, which are potentially more efficient than the SHE, have been recently discovered. The objective of our project is to explore, understand, and improve some of these effects using the spin absorption technique. I will study interfacial systems with surface states where the Rashba spin splitting is large. In these systems, the Rashba-Edelstein effect (REE) is expected to be larger than the bulk counterpart, the SHE. Interfaces with large REE, either metal/metal and metal/insulator bilayers, namely Ta/Cu, Ta/Ag, Cu/Bi2O3 and Ag/Bi2O3, will be explored. In a second stage of the project, I will move on to 3D topological insulators. These materials conduct only at the surface and present an extremely strong spin-orbit coupling causing a spin-momentum locking. Accordingly, we will explore prototypical TI materials such as Bi2Se3, Bi2Te3 and their alloys with Sb, which should provide a novel exciting way of playing with the spin-charge inter-conversion. This will be developed in close connection to the work developed by Early Stage Researcher 9 (LEEDS, United Kingdom) in the 2D analogue systems.