The MCQST Colloquium Series features interdisciplinary talks given by visiting international speakers. The monthly colloquial covers topics spanning all MCQST research units and will be broadcasted live, being made available to audiences worldwide. The main goal of the series is to create the framework for idea exchange, to strengthen links with QST leading groups worldwide, as well as to act as an integral part of the local educational environment.

MCQST Colloquium: Ataç İmamoğlu

On 10 November 2020 , we are excited to invite you to attend the colloquium offered by Ataç İmamoğlu, Professor at the Department of Physics at the ETH Zurich, Switzerland.

Strong electronic correlations in 2D semiconductors

When the Coulomb repulsion between electrons dominates over their kinetic energy, electrons in two dimensional systems were predicted to spontaneously break continuous translation symmetry and form a quantum crystal. Efforts to observe this elusive state of matter, termed a Wigner crystal, in two dimensional extended systems have primarily focused on electrons confined to a single Landau level at high magnetic fields, but have not provided a conclusive experimental signature of the emerging charge order. In this talk, I will present experiments where we use optical spectroscopy to demonstrate that electrons in a pristine monolayer semiconductor form a Wigner crystal. The interactions between resonantly injected excitons and electrons arranged in a periodic lattice modify the exciton band structure so that it exhibits a new umklapp resonance, heralding the presence of charge order. Remarkably, the combination of a relatively high electron mass and reduced dielectric screening allows us to observe electron crystals even in the absence of external magnetic fields.

Online talk

The access link for to access the talk will be distributed via the mailing lists: [mqc-info], [wiss-mpq] and [Mpq-colloquium-stream]. If you already receive mails from [wiss-mpq], there is no need to register to [Mpq-colloquium-stream]. Make sure to subscribe to one of the lists in order to receive the link.

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