title: Tunable spin and valley dependent magneto-optical absorption in molybdenum disulfide quantum dots.
abstract: Photonic quantum computer, quantum communication, quantum metrology and quantum optical technologies rely on the single-photon source (SPS). However, the SPS with valley-polarization remains elusive and the tunability of magneto-optical transition frequency and emission/absorption intensity is restricted, in spite of being highly in demand for valleytronic applications. Here we report a new class of SPSs based on carriers spatially localized in two-dimensional monolayer transition metal dichalcogenide quantum dots (QDs). We demonstrate that the photons are absorbed (or emitted) in the QDs with distinct energy but definite valley-polarization. The spin-coupled valley-polarization is invariant under either spatial or magnetic quantum quantization. However, the magneto-optical absorption peaks undergo a blue shift as the quantization is enhanced. Moreover, the absorption spectrum pattern changes considerably with a variation of Fermi energy. This together with the controllability of absorption spectrum by spatial and magnetic quantizations, offers the possibility of tuning the magneto-optical properties at will, subject to the robust spin-coupled valley polarization.
authors.affiliation: Instituto de Física, Universidade de Brasília, Brasília-DF 70919-970, Brazil.
authors.forename: Fanyao
authors.initials: F
authors.lastname: Qu
authors.affiliation: Instituto de Física, Universidade de Brasília, Brasília-DF 70919-970, Brazil.
authors.forename: A C
authors.initials: AC
authors.lastname: Dias
authors.affiliation: Instituto de Física, Universidade de Brasília, Brasília-DF 70919-970, Brazil.|Department of Physics, Qufu Normal University, Qufu, Shandong, 273165, China.
authors.forename: Jiyong
authors.initials: J
authors.lastname: Fu
authors.affiliation: Instituto de Física, Universidade de Brasília, Brasília-DF 70919-970, Brazil.
authors.forename: L
authors.initials: L
authors.lastname: Villegas-Lelovsky
authors.affiliation: Instituto de Física, Universidade de Brasília, Brasília-DF 70919-970, Brazil.
authors.forename: David L
authors.initials: DL
authors.lastname: Azevedo