Spin phenomena in 2D materials – highly anisotropic magnets at the monolayer limit

• Applicant: Dr. Daniel Weber
• Subject Area: Solid State and Surface Chemistry, Material Synthesis ; Experimental Condensed Matter Physics
• Term: from 2018 to 2019
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 405560254

Single layered van der Waals materials with strong bonding in two dimensions (2D) and weak bonds in the third have galvanized researchers as hosts for previously unobserved physical phenomena such as high mobility Dirac electrons and due to their potential for atomically thin electronic components in devices. Yet, investigations into collective magnetism in 2D compounds only started recently, though they could lead to loss less conduction based on a stack of a 2D ferromagnet and a topological insulator or to spin based computation at the atomic limit. One inhibiting factor is the sparsity of compounds available for experimental studies, which at the moment are restricted to the ferromagnetic insulators CrI3 and Cr2Ge2Te6. The magnetic properties of the latter compounds appear far below liquid nitrogen temperatures (< -196 °C). Here, I propose to synthesize a library of transition metal based intermetallic and cluster van der Waals compounds as well as their monolayers. To achieve these monolayers, I will apply techniques of solid state chemistry to tune the magnetic properties as well as reduce the number of defects which inhibit the separation of the van der Waals layers. The first set of syntheses will focus on creating metallic ferromagnetic monolayer compounds which are magnetic above the temperature of liquid nitrogen, possibly even room temperature. In a second set of experiments, I will investigate how to balance the co- and anti-alignment of spins by reducing the numbers of layer per stack. These subtle interaction could create frustrated magnets which features magnetic interactions on the local scale, but without long range magnetic order. The creation of monolayer compounds exhibiting metallic ferromagnetism or frustrated magnetic behavior are of interest as platforms for condensed matter experiments on the nanoscale and as atomically thin building blocks in spin based and quantum computation.

• DFG Programme: Research Fellowships
• International Connection: USA
• Host: Professor Dr. Joshua Goldberger