Next-gen frustrated magnetism

• Applicant: Professor Dr. Lode Pollet
• Subject Area: Theoretical Condensed Matter Physics
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 530111096

Magnetic frustration has opened a window where quantum many-body entanglement can be studied and manipulated, without being hindered by magnetic order. Its influence has spread across condensed matter in multiferroics, skyrmions, artificial lattices ... and brought to low energy physics the exciting high-energy physics of emergent gauge fields, Majorana fermions, fractons, etc. However, the vast majority of frustrated models belongs to only a handful of geometries. Here we open a new frontier in frustrated magnetism by studying a new geometry, the centred pyrochlore lattice (CPy) that is more versatile than kagome and pyrochlore lattices. In a first paper (Nutakki, 2022), we showed how it is realised in metal-organic frameworks for classical spins. Having established a robust classical spin liquid (Nutakki, 2023), we will now explore beyond the standard classical model along two complementary lines: (A) The CPy contains both U(1) and Z2 spin liquids, whose spectral functions we will compute using large-scale quantum Monte Carlo simulations. The visualization of the spectral functions will lay bare the competition between spin liquids and ordered phases, and also have great pedagogical value. (B) While electromagnetism naturally appears as the low-energy description of some frustrated systems, more complex gauge fields remain rare. This is unfortunate as their quasi-particle excitations bear promising properties for information storage and transport. L. Jaubert is an expert in the systematic inspection of generic frustrated Hamiltonians, which we will apply to the CPy lattice in order to find and design unusual gauge fields, using continuum field theory and Monte Carlo simulations.

• DFG Programme: Research Grants
• International Connection: France
• Cooperation Partner: Dr. Ludovic Jaubert