Exploiting The Valley For Next Generation Electronics

Molybdenum disulfide-based valleytronics have the potential to be the next generation of low energy electronics, scientists say.

AsianScientist (Sep. 9, 2014) – A research group lead by Professor Yoshihiro Iwasa of the University of Tokyo Graduate School of Engineering Quantum-Phase Electronics Center has uncovered peculiar electronic properties of molybdenum disulfide, which has a two dimensional honeycomb crystal structure similar to graphene.

In a study published in Nature Nanotechnology, the research group demonstrated that molybdenum disulfide is an extremely strong candidate material for use in “valleytronics,” a new technology for the development of low energy-consumption electronic devices based on an entirely new principle.

Recently, there have been many concepts proposed for the development of low energy consumption electronics. One of the most fundamental proposals is to replace electrical charge with something else to suppress energy losses as heat generated by electrical current flow, rather than to make improvements on existing technologies.

One promising candidate is “spintronics,” which aims to develop the techniques for manipulating electron spin. Valley is another degree of freedom of electrons that can be found in particular materials. As its manipulation is theoretically predicted, it is attracting researchers’ attention as a new technology called “valleytronics”.

In the present study, researchers have uncovered a strong coupling between valley and spin. The group combined experimental data from spin- and angle-resolved photoemission spectroscopy and circularly polarized photoluminescence spectroscopy on molybdenum disulfide with first-principles calculations, and demonstrated that molybdenum disulfide possesses valley-dependent spin polarization and other characteristics required for application to valleytronics.

Their results matched the theoretical prediction and are an important step toward the development of valleytronics based on molybdenum disulfide, opening the door to next-generation low energy consumption electronics.

The article can be found at: Suzuki et al. (2014) Valley-Dependent Spin Polarization in Bulk MoS2 with Broken Inversion Symmetry.


Source: University of Tokyo.
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