September 2021

Scientists from Australia's Monash University (affiliated with Fleet, the Australian research council funded ‘Arc Centre of Excellence in Future low-energy Electronics Technologies’) have discovered how magnetism occurs in 2D ‘kagome’ metal-organic frameworks, opening the door to self-assembling controllable nano-scale electronic and spintronic devices.

Kagome materials have repeating patterns of hexagons and smaller triangles, with the hexagons touching at their tips. The word 'Kagome' comes from Japanese, relating to a basket weaving pattern.

Researchers at CIC nanoGUNE BRTA in Spain and University of Regensburg in Germany have recently demonstrated spin precession at room temperature in the absence of a magnetic field in bilayer graphene. In their paper, the team used 2D materials to realize a spin field-effect transistor.

Sketch of the spin field-effect transistor. Image from article

Coherently manipulating electron spins at room temperature using electrical current is a major goal in spintronics research. This is particularly valuable as it would enable the development of numerous devices, including spin field-effect transistors. In experiments using conventional materials, engineers and physicists have so far only observed coherent spin precession in the ballistic regime and at very low temperatures. Two-dimensional (2D materials), however, have unique characteristics that could provide new control knobs to manipulate spin procession.

Rice University researchers have confirmed the topological origins of magnons, magnetic features they discovered three years ago in a 2D material that could prove useful for encoding information in the spins of electrons.

The discovery provides a new understanding of topology-driven spin excitations in materials known as 2D van der Waals magnets. The materials are of growing interest for spintronics - for computation, storage and communications.