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Phase transition between different polymorphs of two-dimensional (2D) transition metal dichalcogenides is of great interest for the development of nanoelectronics and optoelectronics. Here, we report the visualization of laser-driven 2H-to-1T′ phase transition in few-layer molybdenum ditelluride (MoTe2) nanosheets by microwave impedance microscopy. The region after intense illumination exhibits clear Raman signatures of the 1T′ phase, as well as much higher local conductance than the untreated area. Moreover, the semiconducting 2H region displays strong photoresponse, whereas the metallic 1T′ region shows little photoconductivity. The spatially resolved information is important for correlating electrical and structural properties in functional 2D materials. 

Magnetic bilayers consisting of an epitaxially grown ferrimagnetic insulator and a heavy metal layer are attractive for spintronic application because of the opportunity for electric control and readout of spin textures via spin–orbit torque. Here, we investigate ultrathin thulium iron garnet (TmIG)/Pt bilayers for TmIG layer thicknesses of 3, 2.7, and 2.3 nm using a sensitive Sagnac magneto-optical Kerr effect technique. We compare the hysteresis loops from out-of-plane and in-plane applied magnetic fields. The preferred magnetization orientation evolves with the TmIG thickness and the presence of the Pt overlayer. We quantify the evolution of the magnetic anisotropy in these ultrathin films and find a significant change even when the TmIG thickness is varied by less than 1 nm. In these ultrathin films, the presence of a Pt overlayer changes the effective anisotropy field by more than a factor of 2, suggesting that the interfacial anisotropy at the Pt/TmIG interface plays a critical role in this regime. 

Semiconductor moiré superlattices, characterized by their periodic spatial light emission, unveil a new paradigm of engineered photonic materials. Here, we show that ferroelectric moiré domains formed in a twisted hexagonal boron nitride (t-hBN) substrate can modulate light emission from an adjacent semiconductor MoSe₂monolayer. The electrostatic potential at the surface of the t-hBN substrate provides a simple way to confine excitons in the MoSe₂monolayer. The excitons confined within the domains and at the domain walls are spectrally separated because of a pronounced Stark shift. Moreover, the patterned light emission can be dynamically controlled by electrically gating the ferroelectric domains, introducing a functionality beyond other semiconductor moiré superlattices. Our findings chart an exciting pathway for integrating nanometer-scale moiré ferroelectric domains with various optically active functional layers, paving the way for advanced nanophotonics and metasurfaces.