Electrostatic Control of Nonlinear Photonic-Crystal Polaritons in a Monolayer Semiconductor.

Integration of 2D semiconductors with photonic crystal slabs provides an attractive approach to achieving strong light-matter coupling and exciton-polariton formation in a chip-compatible geometry. However, for the development of practical devices, it is crucial that polariton excitations are easily tunable and exhibit a strong nonlinear response. Here we study neutral and charged exciton-polaritons in an electrostatically gated photonic crystal slab with an embedded monolayer semiconductor MoSe and experimentally demonstrate a novel approach to optical control based on polariton nonlinearity.

All-optical control of skyrmion configuration in CrI monolayer.

The potential for manipulating characteristics of skyrmions in a CrI monolayer using circularly polarised light is explored. The effective skyrmion-light interaction is mediated by bright excitons whose magnetization is selectively influenced by the polarization of photons. The light-induced skyrmion dynamics is illustrated by the dependencies of the skyrmion size and the skyrmion lifetime on the intensity and polarization of the incident light pulse.

Qubit gate operations in elliptically trapped polariton condensates.

We consider bosonic condensates of exciton-polaritons optically confined in elliptical traps. A superposition of two non-degenerated p-type states of the condensate oriented along the two main axes of the trap is represented by a point on a Bloch sphere, being considered as an optically tunable qubit. We describe a set of universal single-qubit gates resulting in a controllable shift of the Bloch vector by means of an auxiliary laser beam.

Spin-polarized Majorana zero modes in proximitized superconducting penta-silicene nanoribbons.

We theoretically propose penta-silicene nanoribbons (p-SiNRs) with induced p-wave superconductivity as a platform for the emergence of spin-polarized Majorana zero-modes (MZMs). The model explicitly considers the key ingredients of well-known Majorana hybrid nanowire setups: Rashba spin-orbit coupling, magnetic field perpendicular to the nanoribbon plane, and first nearest neighbor hopping with p-wave superconducting pairing. The energy spectrum of the system, as a function of chemical potential, reveals the existence of MZMs with a well-defined spin orientation localized at the opposite ends of both the top and bottom chains of the p-SiNR, associated with well-localized and nonoverlapping wave function profiles.

Photoluminescence imaging of single photon emitters within nanoscale strain profiles in monolayer WSe.

Local deformation of atomically thin van der Waals materials provides a powerful approach to create site-controlled chip-compatible single-photon emitters (SPEs). However, the microscopic mechanisms underlying the formation of such strain-induced SPEs are still not fully clear, which hinders further efforts in their deterministic integration with nanophotonic structures for developing practical on-chip sources of quantum light. Here we investigate SPEs with single-photon purity up to 98% created in monolayer WSe via nanoindentation.