Condensed Matter Seminar: Optics of Van der Waals materials under non-uniform strain

Abstract:

In recent years, Van der Waals (2D) materials, have attracted increasing attention due to their distinctive physical properties. As layered materials, they have been considered for flexible electronics as they can sustain strain higher than 10% without breaking down, although they are only 1-3 atom thick. Their superior mechanical properties led to a renewed interest in the mechanics of thin membranes linked to condensed matter physics. In this talk we will show how we can apply non-uniform strain to a suspended Van der Waals material (WS 2 ) and alter the dynamics of excitons and trions. Surprisingly, we find that as we increase the non-uniformity of the strain, we are able to convert the excitons into trions with almost 100% efficiency without any electrostatic gating. Our results explain inconsistencies in previous experiments and pave the way towards new types of optoelectronic devices. 

Event Organizer: Prof. Eran Sela