The study of pyrite-type materials provides new insights and opportunities for selective spin control in topological spintronics devices.

Seeking new spin in topological materials

Topological materials have exciting potential for next-generation, ultra-low energy electronics, including thermoelectric and spintronic devices.

However, a restriction on the use of such materials in spintronics has been that all topological materials studied thus far have spin states that lie parallel to the plane of the material, while many/most/all practical spintronic devices would require out-of-plane spin states.

Generating and manipulating out-of-plane spins without applying an external electric or magnetic field has been a key challenge in spintronics.

The new Monash Engineering study demonstrates for the first time that pyrite-type crystals can host unconventional energy- and direction-dependent spin textures on the surface, with both in-plane and out-of-plane spin components, in sharp contrast to spin textures in conventional topological materials.

"A number of pyrite-type materials have previously been theoretically predicted to show the desired out-of-plan spin textures," explains lead author Dr Yuefeng Yin, in Monash Engineering's Computational Materials Lab.

Pyrite (colloquially known as 'fool's gold') is an iron-sulfide mineral that displays multiple internal planes of electronic symmetry.

"The presence of strong local symmetry protects out-of-plan spin states," explains Yuefeng, "so we decided to look closer at some of these crystals."

非传统的自旋结构发现打开new possibilities for the necessary task of injecting or detecting out-of-plane spin component in future topological spintronic devices.