談話会・セミナー

第2回 物理工学科教室談話会(講師:Prof. Dr. Atac Imamoglu氏)
2017.04.18

日時:平成29年4月20日(木)10:00~11:30
場所:工学部6号館1階103号室(大会議室)
講師:Prof. Dr. Atac Imamoglu
所属:ETH Zurich
題目:Polaritons in two dimensional systems
Abstract:
Cavity-polaritons have emerged as an exciting platform for studying interacting bosons in a driven-dissipative setting. Typically, the experimental realization of exciton-polaritons is based on undoped GaAs quantum wells (QW) embedded in between two monolithic distributed Bragg reflector (DBR) layers. Introduction of a degenerate electron gas either to the QW hosting the excitons or aneighboring layer substantially enriches the physics due to polariton-electron coupling. It has been proposed that such an interacting Bose-Fermi mixture can be used to study polariton-mediated superconductivity in a two dimensional electron gas.

Transition metal dichalcogenide (TMD) monolayers, such as molybdenum diselenide (MoSe2), represent a new class of valley semiconductors exhibiting novel features such as strong Coulomb interactions, finite exciton Berry curvature with novel optical signatures and locking of spin and valley degrees of freedom due to large spin-orbit coupling. In contrast to quantum wells or two-dimensional electron systems in III-V semiconductors, TMD monolayers exhibit an ultra-large exciton binding energy of order 500 meV and strong trion peaks in photoluminescence that are red-shifted from the exciton line by 30 meV. In this talk, I will present cavity spectroscopy of gate-tunable monolayer MoSe2 exhibiting strongly bound exciton-polaron and trion resonances, as well as non-perturbative coupling to a single microcavity. Our findings constitute a first step in investigation of a new class of degenerate Bose-Fermi mixtures consisting of polaritons and electrons.

紹介教員:樽茶 清悟 教授(物理工学専攻)、中村 泰信 教授(物理工学専攻)

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