Observation of perovskite topological valley exciton-polaritons at room temperature

TL;DR

This paper reports the experimental observation of valley-polarized topological exciton-polaritons in a 2D perovskite lattice at room temperature, demonstrating their potential for topological valleytronic devices.

Contribution

First demonstration of propagating topological exciton-polaritons with valley degree of freedom at room temperature using a 2D valley-Hall perovskite lattice.

Findings

Observation of valley-polarized topological kink states with a 9 meV gap.

Counter-propagating valley-polarized states under resonant excitation.

Verification of valley-dependent topological propagation at room temperature.

Abstract

Topological exciton-polaritons are a burgeoning class of topological photonic systems distinguished by their hybrid nature as part-light, part-matter quasiparticles. Their further control over novel valley degree of freedom (DOF) has offered considerable potential for developing active topological optical devices towards information processing. However, the experimental demonstration of propagating topological exciton-polaritons with valley DOF remains elusive at room temperature. Here, employing a two-dimensional (2D) valley-Hall perovskite lattice, we report the experimental observation of valley-polarized topological exciton-polaritons and their valley-dependent propagations at room temperature. The 2D valley-Hall perovskite lattice consists of two mutually inverted honeycomb lattices with broken inversion symmetry. By measuring their band structure with angle-resolved photoluminescence spectra, we experimentally verify the existence of valley-polarized polaritonic topological kink states with a large gap opening of ~ 9 meV in the bearded interface at room temperature. Moreover, these valley-polarized states exhibit counter-propagating behaviors under a resonant excitation at room temperature. Our results not only expand the landscape of realizing topological exciton-polaritons, but also pave the way for the development of topological valleytronic devices employing exciton-polaritons with valley DOF at room temperature