Real-time tunable notched waveguide based on voltage controllable ferroelectric resonator.

In the present study, we have devised and conducted an investigation into a real-time tunable notched waveguide, employing a voltage-controllable plasmonic resonator. This plasmonic resonator is meticulously engineered from a ferroelectric substrate featuring a compound multilayer structure, thereby conferring it with the remarkable capability of flexible permittivity control. Furthermore, we have implemented two non-intersecting Archimedean spiral electrodes on the surface of the ferroelectric substrate, dedicated to applying the bias field onto the controllable plasmonic ferroelectric resonator (CPFR). Notably, our system affords the capability to finely tune both the magnetic and electric modes, achieving precise adjustments of 8.7% and 11%, respectively. The performance is complemented by minimal insertion loss, rapid response times, and a broad range of potential applications, positioning it as a candidate for a diverse array of notched waveguide scenarios.

Reversible Entropy-Driven Defect Migration and Insulator-Metal Transition Suppression in VO2 Nanostructures for Phase-Change Electronic Switching.

Oxygen defects are among essential issues and required to be manipulated in correlated electronic oxides with insulator-metal transition (IMT). Besides, surface and interface control are necessary but challenging in field-induced electronic switching towards advanced IMT-triggered transistors and optical modulators. Herein, we demonstrated reversible entropy-driven oxygen defect migrations and reversible IMT suppression in vanadium dioxide (VO2 ) phase-change electronic switching. The initial IMT was suppressed with oxygen defects, which is caused by the entropy change during reversed surface oxygen ionosorption on the VO2 nanostructures. This IMT suppression is reversible and reverts when the adsorbed oxygen extracts electrons from the surface and heals defects again. The reversible IMT suppression observed in the VO2 nanobeam with M2 phase is accompanied by large variations in the IMT temperature. We also achieved irreversible and stable IMT by exploiting an Al2 O3 partition layer prepared by atomic layer deposition (ALD) to disrupt the entropy-driven defect migration. We expected that such reversible modulations would be helpful for understanding the origin of surface-driven IMT in correlated vanadium oxides, and constructing functional phase-change electronic and optical devices.

Energy-adaptive resistive switching with controllable thresholds in insulator-metal transition.

Resistive switching has provided a significant avenue for electronic neural networks and neuromorphic systems. Inspired by the active regulation of neurotransmitter secretion, realizing electronic elements with self-adaptive characteristics is vital for matching Joule heating or sophisticated thermal environments in energy-efficient integrated circuits. Here we present energy-adaptive resistive switching via a controllable insulator-metal transition. Memory-related switching is designed and implemented by manipulating conductance transitions in vanadium dioxide. The switching power decreases dynamically by about 58% during the heating process. Furthermore, the thresholds can be controlled by adjusting the insulator-metal transition processes in such nanowire-based resistive switching, and then preformed in a wide range of operating temperatures. We believe that such power-adaptive switching is of benefit for intelligent memory devices and neuromorphic electronics with low energy consumption.

Integrated spoof plasmonic circuits.

Using a metamaterial consisting of metals with subwavelength surface patterning, one can mimic surface plasmon polaritons (SPPs) and achieve surface waves with subwavelength confinement at microwave and terahertz frequencies, thus bringing most of the advantages associated with the optical SPPs to lower frequencies. Due to the properties of strong field confinement and high local field intensity, spoof SPPs have demonstrated the improved performance for data transmission and device miniaturization in an intensively integrated environment. The distinctive abilities, such as suppression of transmission loss and bending loss, and increase of signal integrity, make spoof SPPs a promising candidate for future generation of electronic circuits and electromagnetic systems. This article reviews the progress in spoof SPPs with a special focus on their applications in circuits from transmission lines to passive and active devices in microwave and terahertz regimes. The integration of versatile spoof SPP devices on a single platform, which is compatible with established electronic circuits, is also discussed.