Tunable spin and valley dependent magneto-optical absorption in molybdenum disulfide quantum dots

• Published in: Scientific reports Vol. 7; no. 1; p. 41044
• Main Authors: Qu, Fanyao, Dias, A. C., Fu, Jiyong, Villegas-Lelovsky, L., Azevedo, David L.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 23.01.2017; Nature Publishing Group
• Subjects: 639/301/119/997; 639/624/399/1017; Absorption; Energy; Humanities and Social Sciences; Molybdenum; Molybdenum disulfide; multidisciplinary; Optical properties; Photons; Polarization; Quantum dots; Quantum theory; Science
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/srep41044

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.