Dynamics in chiral magnets -Helimagnons in MnSi under pressure: Towards the non-Fermi liquid phase

• Applicant: Dr. Robert Georgii
• Subject Area: Experimental Condensed Matter Physics
• Term: from 2015 to 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 270344603

In the previous project we have reached a full theoretical understanding of the (B, T)-phase diagram of MnSi and its underlying dynamical processes based on only three input parameters, the strength of the DM interaction, the stiffness of the magnetic spiral under magnetic field and the anharmonicity of the magnetic spin system.This will allow us to continue in the understanding of the role of the anisotropy and the fluctuations in MnSi as we extend the parameter space to applied pressure. Here we are interested in how the magnetic spiral develops with pressure and if there is new physics when approaching the critical pressure of 14.6 kbar. We would furthermore like to explore the behaviour of MnSi under pressure and field simultaneously, eventually testing the skyrmion regime. Finally, we plan to reach the critical pressure and above both in zero field and with applied magnetic field. This will enable us to test whether the non-Fermi liquid behaviour above the critical pressure is related to the spin dynamics of the skyrmion lattice. This will help to establish a connection between magnetic fluctuations and topological magnetic structures.

• DFG Programme: Research Grants
• International Connection: USA
• Cooperation Partners: Professor Dr. Peter Böni; Professor Dr. Markus Garst; Dr. Marc Janoschek