Exciton routing in the heterostructure of TMD and quantum paraelectrics

V. Shahnazaryan, O. Kyriienko, H. Rostami

Published 2019-02-20Version 1

We propose a scheme for the spatial exciton binding energy control and exciton routing in transition metal dichalcogenide (TMD) monolayer which lies on a quantum paraelectric substrate. It relies on the ultrasensitive response of the substrate dielectric permittivity to temperature changes, allowing for spatially inhomogeneous screening of Coulomb interaction in the monolayer. As an example, we consider the heterostructure of TMD and strontium titanate oxide SrTiO$_3$, where large dielectric screening can be attained. We study the impact of substrate temperature on the characteristic features of excitons such as the binding energy, Bohr radius and exciton nonlinearity (an exciton-exciton interaction). Applying local heating, we create spatial patterns with varying exciton binding energy and an exciton flow towards the energetically lower region of the sample. The proposed scheme has potential for the creation of exciton-based logic gates and efficient light-harnessing devices.