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Fermi-edge polaritons with finite hole mass

Dimitri Pimenov, LMU

29.05.2015 at 12:15 

Microcavity polaritons are half-light-half-matter eigenmodes of a quasi two-dimensional system where a direct  semiconductor quantum well is embedded in an optical resonator. For polaritons to appear, the cavity photon mode must be tuned close to an optical transition of the semiconductor. When the semiconductor is heavily n-doped, the relevant transition corresponds to the so-called Fermi-edge singularity, leading to the formation of two split Fermi-edge polariton branches.
Previous theoretical studies of Fermi-edge polaritons have been mostly restricted to an infinite valence band hole mass, which is appropriate for low-mobility samples. To describe high-mobility samples, we study the implications of a finite hole mass. Using the diagrammatic approach initiated by Mahan and Nozieres, we analytically compute the finite mass Fermi-edge singularity, finding that the hole recoil washes out the pole structure with a 2D-specific power law.
We show that this results in a reduced splitting of the polariton branches, which qualitatively agrees with a recent experiment.

A 450 - Theresienstr. 37