Thorium Compounds Unveil Potent Spin and Heat Properties

Researchers have identified a family of thorium-based compounds—specifically ThAsS, ThAsSe, and ThSbSe—that could play a pivotal role in future electronics. Through systematic ab initio modelling, the study reveals these materials possess non-trivial topological properties, meaning their electronic structures are robust and uniquely organised.

The investigation highlights significant Spin Hall and Spin Nernst effects within these crystals. The Spin Hall effect allows for the generation of spin currents via electricity, while its counterpart, the Spin Nernst effect, achieves this using heat—a phenomenon essential for the field of spin-caloritronics. Crucially, the study found that the flow of spin can be finely tuned; by altering the electric field direction or adjusting the Fermi level (the energy limit of the electrons), the conductivity can be amplified or reversed.

Additionally, an analysis of phonons—quantised vibrations in the crystal lattice—uncovered exotic features, such as a ‘Z-centred hourglass nodal loop’ in ThAsS. These findings underscore the potential of thorium compounds for exploring complex topological physics and developing efficient spin-current devices.