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2014-11-13 | Corporate

Honorable “Dirac fermions”

Every year Anton Paar bestows two awards, one for research in physics the other for research in chemistry. These awards honor the work of young scientists. The 2014 Anton Paar Award for Physics goes to Dr. René Hammer for his PhD "Dynamics of Dirac Fermions" (Institute of Physics, University of Graz).

What is the focus of the dissertation? The young physicist explains:

An insulator is a material which does not conduct electrical current. For quite a long time it was thought that all electrical insulators could be described by this definition. However, recently it was found that there are two different kinds of insulators: The ordinary insulators, with vacuum being a member of this class, and topological non-trivial insulators. The latter insulators show special states on the surface which are protected by time-reversal symmetry. This leads to an electrical conductive layer on the surface which builds up holographically from the properties of the bulk and cannot be destroyed by damaging the surface. The current is carried by so-called Dirac fermions. Because of the special properties of these Dirac fermions, a current always magnetizes the surface. Within the PhD thesis a numerical scheme, which allows for an efficient simulation of the Dirac fermions, was developed. The scheme avoids the occurrence of additional unphysical solutions in the numerical simulation which have plagued finite difference schemes until now. This so-called fermion-doubling problem was solved by a special staggering of the numerical grid in space and time. Utilizing this scheme it was possible to investigate the dynamics of electrical one-way channels formed at magnetic domain walls on the topological insulator surface and to propose electrical networks with these domain-wall fermions. Besides new findings in solid-state physics this could lead to new opportunities for low energy consuming microelectronics and sensor applications.

Congratulations to Dr. René Hammer! We wish him continued success in his career.

Dr. René Hammer:
2003 to 2010: Degree in Technical Physics at the TU Graz, diploma thesis: “Quantum-Quench in N-Chain Luttinger Liquids”, Supervisor: Prof. Dr. Enrico Arrigoni
2010 to 2013: PhD in Physics at the Karl-Franzens University Graz, PhD: “Dynamics of Dirac Fermions”, Supervisor: Prof. Dr. Walter Pötz
2014 to current day: Scientist at Materials Center Leoben (MCL)
Current research focus: Simulation of thermal transport and thermomechanical stresses, material models, damage and breakage concepts in microelectronics, propagation of ultrasound in solids.