Science Daily September 8, 2023
The two degenerate valleys in transition metal dichalcogenides can be used to store and process information for quantum information science and technology. A major challenge is maintaining valley polarization at room temperature where phonon-induced intervalley scattering is prominent. A team of researchers in the US (Brookhaven National Laboratory, industry) has demonstrated room temperature valley polarization in heterostructures of monolayer MoS2 and naphthylethylammine based one-dimensional chiral lead halide perovskite. By optically exciting the heterostructures with linearly polarized light close to resonance and measuring the helicity resolved photoluminescence, they obtained a degree of polarization of up to −7% and 8% in MoS2/right-handed (R-(+)-) and left-handed (S-(-)-) 1-(1-naphthyl)ethylammonium lead iodide perovskite, respectively. They attributed this to spin selective charge transfer from MoS2 to the chiral perovskites where the perovskites act as a spin filter due to their chiral nature. According to the researchers their study provides a simple, and robust route to obtain room temperature valley polarization, paving the way for practical valleytronics devices… read more. Open Access TECHNICAL ARTICLE
Photoluminescence with circularly polarized excitation. Credit: Nature Communications volume 14, Article number: 5234 (2023)