Condensed-Matter Seminar:"Exciton and trions in Van der Waals materials and their dynamics under different non-uniform strain configurations"

Date: 
Mon, 16/12/2019 - 12:00 to 13:30

Location: 
Danciger B building, Seminar room
Lecturer:  Dr. Moshe Harats, Faculty of Physics, Freie University Berlin
Abstract:

In recent years, Van der Waals (2D)materials, have attracted increasing attention due to their distinctivephysical properties. As layered materials, they have been considered for flexibleelectronics as they can sustain strain higher than 10% without breaking down,although they are only 1-3 atom thick. Their superior mechanical properties ledto a renewed interest in the mechanics of thin membranes linked to condensedmatter physics. In this talk we will show how we can apply non-uniform strainto a suspended Van der Waals material (WS2) and alter the dynamicsof excitons and trions. Surprisingly, we find that as we increase thenon-uniformity of the strain, we are able to convert the excitons into trionswith almost 100% efficiency without any electrostatic gating. Our resultsexplain inconsistencies in previous experiments and pave the way towards newtypes of optoelectronic devices.