Dephasing of InAs quantum dot p -shell excitons studied using two-dimensional coherent spectroscopy

Suzuki, T. and Singh, R. and Moody, G. and Aßmann, M. and Bayer, M. and Ludwig, Ar. and Wieck, A.D. and Cundiff, S.T.

Volume: 98 Pages:
DOI: 10.1103/PhysRevB.98.195304
Published: 2018

The dephasing mechanisms of p-shell and s-shell excitons in an InAs self-assembled quantum dot ensemble are examined using two-dimensional coherent spectroscopy (2DCS). 2DCS provides a comprehensive picture of how the energy level structure of dots affects the exciton dephasing rates and recombination lifetimes. We find that at low temperatures, dephasing of s-shell excitons is lifetime limited, whereas p-shell excitons exhibit significant pure dephasing due to scattering between degenerate spin states. At elevated temperatures, quadratic exciton-phonon coupling plays an important role in both s-shell and p-shell exciton dephasing. We show that multiple p-shell states are also responsible for stronger phonon dephasing for these transitions. © 2018 American Physical Society.

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