Twist angle-dependent valley polarization switching in heterostructures.

The twist engineering of moiré superlattice in van der Waals heterostructures of transition metal dichalcogenides can manipulate valley physics of interlayer excitons (IXs), paving the way for next-generation valleytronic devices. However, the twist angle-dependent control of excitonic potential on valley polarization is not investigated so far in electrically controlled heterostructures and the physical mechanism underneath needs to be explored. Here, we demonstrate the dependence of both polarization switching and degree of valley polarization on the moiré period.

Revealing broken valley symmetry of quantum emitters in WSe with chiral nanocavities.

Single photon emission of quantum emitters (QEs) carrying internal degrees of freedom such as spin and angular momentum plays an important role in quantum optics. Recently, QEs in two-dimensional semiconductors have attracted great interest as promising quantum light sources. However, whether those QEs are characterized by the same valley physics as delocalized valley excitons is still under debate.

Controllable spin-resolved photon emission enhanced by a slow-light mode in photonic crystal waveguides on a chip.

We report the slow-light enhanced spin-resolved in-plane emission from a single quantum dot (QD) in a photonic crystal waveguide (PCW). The slow light dispersions in PCWs are designed to match the emission wavelengths of single QDs. The resonance between two spin states emitted from a single QD and a slow light mode of a waveguide is investigated under a magnetic field with Faraday configuration.

Single charge control of localized excitons in heterostructures with ferroelectric thin films and two-dimensional transition metal dichalcogenides.

Single charge control of localized excitons (LXs) in two-dimensional transition metal dichalcogenides (TMDCs) is crucial for potential applications in quantum information processing and storage. However, traditional electrostatic doping method by applying metallic gates onto TMDCs may cause inhomogeneous charge distribution, optical quenching, and energy loss. Herein, by locally controlling the ferroelectric polarization of the ferroelectric thin film BiFeO (BFO) with a scanning probe, we can deterministically manipulate the doping type of monolayer WSe to achieve p-type and n-type doping.

Enhanced Valley Polarization in WS /LaMnO Heterostructure.

Monolayer transition metal dichalcogenides have attracted great attention for potential applications in valleytronics. However, the valley polarization degree is usually not high because of the intervalley scattering. Here, a largely enhanced valley polarization up to 80% in monolayer WS under nonresonant excitation at 4.

Self-Luminescence of Perovskite-Like LaSrGaO via Intrinsic Defects and Anomalous Luminescence Analysis of LaSrGaO:Mn.

A series of deep red phosphors with perovskite-like oxide LaSrGaO as host are synthesized by a high temperature solid state method, and the luminescence properties and mechanisms have been investigated in detail. LaSrGaO presents self-luminescence at 722 nm, and it is proved that the self-luminescence comes from two kinds of electronic defects and three kinds of vacancy defects, which are anti-occupation defects La , strontium gap defects Sr , the oxygen interstitial defects O , substitution defects Sr , and strontium vacancy defects V . In addition, when Mn ions are doped in LaSrGaO, interestingly, the shape of the emission spectra of LaSrGaO:Mn is the same as that of LaSrGaO, and the emission intensities are enhanced greatly.