Metallic quantum phase transitions: Magnetic anisotropies, crossovers, and multicriticality
The physics of zero-temperature magnetic phase transitions in metals constitutes a major challenge for theory because the critical degrees of freedom, magnetic fluctuations, couple to low-energy particle-hole excitations in a non-trivial fashion. This project is devoted to two different aspects of such quantum phase transitions. First, the goal is to investigate the interplay of magnetic anisotropies and fluctuation effects: there are indications that order-parameter fluctuations can lead to effectively energy-dependent anisotropies, such that different anisotropies show up in different probes. This shall be investigated in detail, including the relevant quantum-to-classical crossover. Second, the project will study metallic quantum multicritality, i.e., a situation where two quantum critical phenomena coincide. This is particularly fascinating if the two are characterized by different dynamic exponents, leading to distinct energy scales near criticality. The theory work will be performed in close contact with experimental activities at MPI-CPfS where a variety of metallic quantum ferromagnets are investigated in detail.
You will spend the majority of your time performing theoretical research at TU Dresden, and, in addition, you will contribute to the analysis of experimental data at MPI-CPfS.