Researchers improve a 2D ferromagnetic materials by layering with a topological insulator to reveal stronger, tuneable behaviour for next-generation quantum gadgets
Alternate-coupled interfaces provide a strong path to stabilising and enhancing ferromagnetic properties in two-dimensional supplies, akin to transition metallic chalcogenides. These supplies exhibit sturdy correlations amongst cost, spin, orbital, and lattice levels of freedom, making them an thrilling space for emergent quantum phenomena.
Cr₂Te₃’s crystal construction naturally varieties layers that behave like two-dimensional sheets of magnetic materials. Every layer has magnetic ordering (ferromagnetism), however the layers usually are not tightly bonded within the third dimension and are thought-about “quasi-2D.” These layers are helpful for interface engineering. Utilizing a vacuum-based method for atomically exact thin-film progress, often called molecular beam epitaxy, the researchers show wafer-scale synthesis of Cr₂Te₃ all the way down to monolayer thickness on insulating substrates. Remarkably, strong ferromagnetism persists even on the monolayer restrict, a essential milestone for 2D magnetism.
When Cr₂Te₃ is proximitized (an impact that happens when one materials is positioned in shut bodily contact with one other in order that its properties are influenced by the neighbouring materials) to a topological insulator, particularly (Bi,Sb)₂Te₃, the Curie temperature, the edge between ferromagnetic and paramagnetic phases, will increase from ~100 Ok to ~120 Ok. This enhancement is experimentally confirmed by way of polarized neutron reflectometry, which reveals a considerable increase in magnetization on the interface.
Theoretical modelling attributes this magnetic enhancement to the Bloembergen–Rowland interplay which is a long-range trade mechanism mediated by digital intraband transitions. Crucially, this interplay is facilitated by the topological insulator’s topologically protected floor states, that are spin-polarized and strong in opposition to dysfunction. These states allow long-distance magnetic coupling throughout the interface, suggesting a common mechanism for Curie temperature enhancement in topological insulator-coupled magnetic heterostructures.
This work not solely demonstrates a technique for stabilizing 2D ferromagnetism but in addition opens the door to topological electronics, the place magnetism and topology are co-engineered on the interface. Such methods might allow novel quantum hybrid gadgets, together with spintronic elements, topological transistors, and platforms for realizing unique quasiparticles like Majorana fermions.
Do you wish to study extra about this matter?
Interacting topological insulators: a overview by Stephan Rachel (2018)
