Nanowerk October 24, 2019
Valleytronics is very attractive for future electronic devices and quantum computing technology. However, the phonon-assisted intervalley scattering accelerates dramatically when temperature is increased, resulting in volatile valley states and significantly reduced handedness of far-field photoluminescence at room temperature. A team of researchers in the US (UT Austin, University of Pennsylvania) addressed these issues by manipulating strong light-matter interactions between valley excitons, and a purpose-designed plasmonic chiral metamaterial. In demonstration they were able to actively and reversibly tune and turn ON/OFF the manipulation. These results provide a new way to control quantum information carriers in 2D materials. Monolayer semiconductors, particularly transition metal dichalcogenides (i.e. MoS2, WSe2, WS2, etc.), feature rich valley-contrasting phenomena at Κ and Κ’ points in the Brillouin zone. The work offers a novel strategy to versatilely control valley excitons in monolayer semiconductors, benefiting applications in ultrathin valleytronic and optoelectronic devices enabling ultrafast switching and control at room temperature…read more. TECHNICAL ARTICLE
Schematics of modulating valley dynamics in monolayer WSe2 using chiral Purcell effects in moiré chiral metamaterials (MCMs). Credit: Reprinted with permission by Wiley-VCH Verlag.