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Improving the photon-magnon coupling strength can be done by tuning the structure of microwave resonators to better interact with the magnon counterpart. Planar resonators accommodating unconventional photon modes beyond the half- and quarter-wavelength designs have been explored due to their optimized mode profiles and potentials for on-chip integration. Here, we designed and fabricated an actively controlled ring resonator supporting the spoof localized surface plasmons (LSPs), and implemented it in the investigation of photon-magnon coupling for hybrid magnonic applications. We demonstrated gain-assisted photon-magnon coupling with the YIG magnon mode under several different sample geometries. The achieved coupling amplification largely benefits from the high quality factor (Q-factor) due to the additional gain provided by a semiconductor amplifier, which effectively increases the Q-factor from a nearly null state (passive resonance) to more than 1000 for a quadrupole LSP mode. Our results suggest an additional control knob for manipulating photon-magnon coupled systems exploiting external controls of gain and loss. 

Abstract Van der Waals semiconductors (vdWS) offer superior mechanical and electrical properties and are promising for flexible microelectronics when combined with polymer substrates. However, the self‐passivated vdWS surfaces and their weak adhesion to polymers tend to cause interfacial sliding and wrinkling, and thus, are still challenging the reliability of vdWS‐based flexible devices. Here, an effective covalent vdWS–polymer lamination method with high stretch tolerance and excellent electronic performance is reported. Using molybdenum disulfide (MoS₂)and polydimethylsiloxane (PDMS) as a case study, gold–chalcogen bonding and mercapto silane bridges are leveraged. The resulting composite structures exhibit more uniform and stronger interfacial adhesion. This enhanced coupling also enables the observation of a theoretically predicted tension‐induced band structure transition in MoS₂. Moreover, no obvious degradation in the devices’ structural and electrical properties is identified after numerous mechanical cycle tests. This high‐quality lamination enhances the reliability of vdWS‐based flexible microelectronics, accelerating their practical applications in biomedical research and consumer electronics. 

Abstract The difficulty of achieving ohmic contacts is a long‐standing challenge for the development and integration of devices based on 2D materials, due to the large mismatch between their electronic properties and those of both traditional metal‐based and van der Waals (vdWs) electrodes. Research has focused primarily on the electronic energy band alignment, while the effects of momentum mismatch on carrier transport across the vdWs gaps are largely neglected. Graphene‐silicon junctions are utilized to demonstrate that electron momentum distribution can dominate the electronic properties of vdWs contacts. By judiciously introducing scattering centers at the interface that provide additional momentum to compensate the momentum mismatch, the junction conductivity is enhanced by more than three orders of magnitude, enabling the formation of high‐quality ohmic contacts. The study establishes the framework for the design of high‐performance ohmic vdWs contacts based on both energy and momentum matching, which can facilitate efficient heterogeneous integration of 2D–3D systems and the development of post‐CMOS architectures. 

Abstract It is widely accepted that solid‐state membranes are indispensable media for the graphene process, particularly transfer procedures. But these membranes inevitably bring contaminations and residues to the transferred graphene and consequently compromise the material quality. This study reports a newly observed free‐standing graphene‐water membrane structure, which replaces the conventional solid‐state supporting media with liquid film to sustain the graphene integrity and continuity. Experimental observation, theoretical model, and molecular dynamics simulations consistently indicate that the high surface tension of pure water and its large contact angle with graphene are essential factors for forming such a membrane structure. More interestingly, water surface tension ensures the flatness of graphene layers and renders high transfer quality on many types of target substrates. This report enriches the understanding of the interactions on reduced dimensional material while rendering an alternative approach for scalable layered material processing with ensured quality for advanced manufacturing.