Multiparticle Excitations, Spin-orbit Coupling, and Magnetism in the Photophysics of Quasi 2D Semiconductors

 · Invited

Abstract

Strong electron-hole interaction and spin-orbit coupling, as well as magnetic ordering, can give rise to novel features in the photophysics of 2D semiconductors. Using the ab initio many-body interacting Green’s function approach, we investigate manifestations of these interactions in several atomically thin 2D materials. We show that electron-hole exchange interaction in monolayer transition metal dichalcogenides (TMDs) mixes the prominent A and B excitons that heretofore were believed to be completely independent of each other, since they had been viewed as derived from inter-band transitions between different pairs of spin-polarized bands. We clarify the physical origin of giant excitonic and magneto-optical responses in monolayer CrI3, a 2D ferromagnetic semiconductor, showing that these properties are dominated by extended exciton states. Finally, with a newly developed approach, we perform ab initio calculations on the properties of trions and bi-excitons in monolayer TMDs, elucidating the energetics and the wavefunction characters of these strongly bounded correlated 3-particle and 4-paricle excitations in 2D semiconductors.

*This work was supported by the U.S. DOE under Contract No. DE-AC02-05CH11231 and by the National Science Foundation, and was done in collaboration with Andrea Cepellotti, Ting Cao, Felipe da Jornada, Zhenglu Li, and Meng Wu. Computational resources have been provided by NERSC and XSEDE.

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Presenters

  • Steven G Louie

    • University of California, Berkeley
    • Department of Physics, University of California, Berkeley
    • University of California at Berkeley and Lawrence Berkeley National Laboratory
    • UC Berkeley & Lawrence Berkeley National Laboratory
    • University of California at Berkeley, and Lawrence Berkeley National Laboratory
    • Lawrence Berkeley National Laboratory
    • Department of physics, University of California at Berkeley, Berkeley, California

Authors

  • Steven G Louie

    • University of California, Berkeley
    • Department of Physics, University of California, Berkeley
    • University of California at Berkeley and Lawrence Berkeley National Laboratory
    • UC Berkeley & Lawrence Berkeley National Laboratory
    • University of California at Berkeley, and Lawrence Berkeley National Laboratory
    • Lawrence Berkeley National Laboratory
    • Department of physics, University of California at Berkeley, Berkeley, California