Science Daily  October 28, 2019 Development of valleytronics requires stable valley states and easy identification of the valley indices. An international team of researchers (USA- UC Riverside, Japan, Taiwan) have shown that dark excitons and trions in monolayer WSe2 have much longer lifetime and better valley stability than the common bright excitons and trions, therefore, serve as excellent candidates for valleytronic applications. Until now no method could read the valley indices of the dark excitons and trions because their light emission from either valley has exactly the same energy and polarization, making the two valleys indistinguishable from each other. They […]