Regensburg 2016 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 44: Optical Properties I

HL 44.6: Vortrag

Mittwoch, 9. März 2016, 11:30–11:45, H10

Exciton-Polaritons in doped semiconductor microcavities with finite hole mass — •Dimitri Pimenov¹, Oleg Yevtushenko¹, Jan von Delft¹, and Moshe Goldstein² — ¹Arnold Sommerfeld Center for Theoretical Physics, Ludwig-Maximilians-Universität München, D-80333 München, Germany — ²School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978, Israel

As shown in recent experiments, spectral properties of exciton-polaritons in optical microcavities with an embedded semiconductor quantum well are strongly affected by doping of the semiconductor. Previous theoretical studies concerned with nonzero Fermi-energy mostly relied on the approximation of infinite valence band hole mass, which is appropriate for low-mobility samples only. For high-mobility samples, one needs to consider large but finite hole mass. We present an analytical diagrammatic approach to tackle this problem for a model of short-ranged (screened) electron-hole interaction, studying its two different regimes. In the first regime, where the Fermi-energy dominates over the exciton binding energy, one can make use of the summation of parquet diagrams introduced by Mahan and Nozières. As a trend, finite mass effects cut off the excitonic features in the polariton spectra, in qualitative agreement with the experimental findings. In the second regime of dominant binding energy, we perform a low-density summation of ladder diagrams. As opposed to the previous case, the excitonic features are enhanced by the finite mass, which can be understood based on phase-space arguments.