Electrically tunable Berry curvature and strong light-matter coupling in liquid crystal microcavities with 2D perovskite

Abstract

The field of spinoptronics is underpinned by good control over photonic spin-orbit coupling in devices that have strong optical nonlinearities. Such devices might hold the key to a new era of optoelectronics where momentum and polarization degrees of freedom of light are interwoven and interfaced with electronics. However, manipulating photons through electrical means is a daunting task given their charge neutrality. In this work, we present electrically tunable microcavity exciton-polariton resonances in a Rashba-Dresselhaus spin-orbit coupling field. We show that different spin-orbit coupling fields and the reduced cavity symmetry lead to tunable formation of the Berry curvature, the hallmark of quantum geometrical effects. For this, we have implemented an architecture of a photonic structure with a two-dimensional perovskite layer incorporated into a microcavity filled with nematic liquid crystal. Our work interfaces spinoptronic devices with electronics by combining electrical control over both the strong light-matter coupling conditions and artificial gauge fields.

Coherent Spin Dynamics of Electrons in Two-Dimensional (PEA)2PbI4 Perovskites

“…In these two-dimensional (2D) structures the exciton binding energy is greatly increased up to 200–500 meV due to the reduction of dimensionality and the dielectric confinement . In this respect, they are similar to 2D materials like the transition-metal dichalcogenides. , Recently perovskite materials have regained strong interest due to the great progress of lead halide perovskites and have advanced as versatile platform for optoelectronic applications − and beyond . In photovoltaics a power conversion efficiency above 17% , was reached, and long-term stability was reported …”

“…A variety of optical methods, like four-wave mixing, spatially resolved spectroscopy, second harmonic generation, and strong coupling in cavities, were used to address the optical properties of exciton complexes in 2D perovskites. The application of high magnetic fields up to 60 T delivered information about the exciton binding energy, effective mass, fine structure, and g -factor. − Time-resolved transmission was used to study the exciton spin dynamics at picosecond and subpicosecond time scales. − However, in these reports, performed at temperatures above liquid nitrogen temperature up to ambient conditions, the spin dynamics was significantly limited, and spin relaxation times exceeding a few picoseconds have not been reported so far.…”

“…12 In photovoltaics a power conversion efficiency above 17% 13,14 was reached, and long-term stability was reported. 15 A variety of optical methods, like four-wave mixing, 16 spatially resolved spectroscopy, 14 second harmonic generation, 17 and strong coupling in cavities, 8 were used to address the optical properties of exciton complexes in 2D perovskites. The application of high magnetic fields up to 60 T delivered information about the exciton binding energy, effective mass, fine structure, and g-factor.…”

Molecular and solid-state topological polaritons induced by population imbalance

“…In experiments, the Berry curvature of photon bands in a Fabry-Perot cavity can be extracted from the components of the Stokes vector 25,26 . However, in the case of exciton-polariton bands, the Berry curvature of only sections of the band that are predominantly photonic and have negligible molecular character 49 can be measured experimentally as, to the best of our knowledge, it is difficult to obtain the phase relationship between the photonic and molecular components, unless lightmatter cross-correlation functions are measured.…”

“…More recently, polaritons in Fabry-Perot cavities have emerged as a viable platform for topological polaritonics. Several experiments have demonstrated measurement and control of the Berry curvature of excitonpolariton and photon bands in these systems [23][24][25][26] . Our work will focus on these Fabry-Perot cavity systems.…”