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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.

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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