Room temperature valley polarization via spin selective charge transfer

Shreetu Shrestha; Mingxing Li; Suji Park; Xiao Tong; Donald DiMarzio; Mircea Cotlet

doi:10.1038/s41467-023-40967-7

Room temperature valley polarization via spin selective charge transfer

Nat Commun. 2023 Aug 26;14(1):5234. doi: 10.1038/s41467-023-40967-7.

Authors

Shreetu Shrestha¹, Mingxing Li², Suji Park², Xiao Tong², Donald DiMarzio³, Mircea Cotlet⁴

Affiliations

¹ Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY, 11973, USA. sshrestha@bnl.gov.
² Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY, 11973, USA.
³ Northrop Grumman Corporation, One Space Park, Redondo Beach, CA, 90278, USA.
⁴ Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY, 11973, USA. cotlet@bnl.gov.

Abstract

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. Here we demonstrate 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, we obtain 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. We attribute 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. Our study provides a simple, yet robust route to obtain room temperature valley polarization, paving the way for practical valleytronics devices.