KTH/Nordita/SU seminar in Theoretical Physics

Collective phenomena in semiconductor microcavities

by Ivan A. Shelykh (University of Iceland)



A semiconductor microcavity is a photonic structure designed to enhance the light-matter interaction. The cavity photons are confined between two mirrors and resonantly interact with the excitonic transition of a 2-dimensional semiconductor quantum well. In strong coupling regime the normal modes of the system are cavity polaritons that are half-light, half-matter quasiparticles. Being composite objects, polaritons inherit the properties of both cavity photons and excitons. The presence of the photonic component results in extremely small effective mass of cavity polaritons (10-4- 10-5 of free electron mass), while excitonic component leads to the efficient polariton- polariton interactions. This makes cavity polaritons a unique laboratory for study of the quantum collective phenomena, including:
1. High temperature BEC
2. Superfluidity
3. Bistability and multistability
4. Unconventional superconductivity
In the talk we plan to give an overview of the polariton physics and in this context discuss the effects mentioned above.