title: Valley and spin dynamics in MoSe2 two-dimensional crystals.
abstract: We study valley and spin dynamics in monolayer molybdenum diselenide by polarization-resolved femtosecond transient absorption spectroscopy. Valley- and spin-polarized excitons are injected by a circularly polarized laser pulse, with an excess energy of 120 meV. Relaxation of the valley polarization is time-resolved by measuring dynamical circular dichroism of a linearly polarized probe pulse tuned to 790 nm, the peak of the exciton resonance of monolayer MoSe2. We obtain a valley relaxation time of 9 ± 3 ps at room temperature, which is at least one order of magnitude shorter than the simultaneously measured exciton lifetime. The results illustrate potential applications of MoSe2 in room-temperature valleytronic and spintronic devices.
authors.affiliation: Department of Physics and Astronomy, The University of Kansas, Lawrence, Kansas 66045, USA. huizhao@ku.edu.
authors.forename: Nardeep
authors.initials: N
authors.lastname: Kumar
authors.forename: Jiaqi
authors.initials: J
authors.lastname: He
authors.forename: Dawei
authors.initials: D
authors.lastname: He
authors.forename: Yongsheng
authors.initials: Y
authors.lastname: Wang
authors.forename: Hui
authors.initials: H
authors.lastname: Zhao