Optical transitions, exciton radiative decay, and valley coherence in lead chalcogenide quantum dots

Abstract

We propose the concept of valley coherence and superradiance in the reciprocal space and show that it leads to an $N$-fold decrease of the bright exciton radiative lifetime in quantum dots (QDs) of an $N$-valley semiconductor. Next we explain why, despite this, the exciton radiative lifetimes in PbX (X = S, Se, Te) QDs, measured from the photoluminescence decay, are in the microsecond range. We also address peculiarities of the light-matter interaction in nanostructures made of narrow-gap materials with strong inter-band coupling.

13 pages, 4 figures

Cited by in corpus (3)

• Coherent spin dynamics of excitons in strained monolayer semiconductors
• Effective Landé factors of electrons and holes in lead chalcogenide nanocrystals
• Untangling the valley structure of states for intravalley exchange anisotropy in lead chalcogenides quantum dots