A 1.25-GHz multi-amplitude modulator driver in 0.18 µm SiGe BiCOMOS technology for high speed quantum key distribution.

Quantum key distribution (QKD) research has yielded highly fruitful results and is currently undergoing an industrialization transformation. In QKD systems, electro-optic modulators are typically employed to prepare the required quantum states. While various QKD systems operating at GHz repetition frequency have demonstrated exceptional performance, they predominantly rely on instruments or printed circuit boards to fulfill the driving circuit function of the electro-optic modulator. Consequently, these systems tend to be complex with low integration levels. To address this challenge, we have introduced a modulator driver integrated circuit in 0.18 µm SiGe BiCMOS technology. The circuit can generate multiple-level driving signals with a clock frequency of 1.25 GHz and a rising edge of ∼50 ps. Each voltage amplitude can be independently adjusted, ensuring the precise preparation of quantum states. The measured signal-to-noise ratio was more than 17 dB, resulting in a low quantum bit error rate of 0.24% in our polarization-encoding system. This work will contribute to the advancement of QKD system integration and promote the industrialization process in this field.

Reshaping Inner Helmholtz Layer and Electrolyte Structure via Multifunctional Organic Molecule Enabling Dendrite-Free Zn Metal Anode.

The dendrite growth and parasitic reactions that occur on Zn metal anode (ZMA)/electrolyte interface hinder the development of aqueous zinc ion batteries (AZIBs) in next-generation renewable energy storage systems. Fortunately, reconstructing the inner Helmholtz layer (IHL) by introducing an electrolyte additive, is viewed as one of the most promising strategies to harvest the stable ZMA. Herein, (4-chloro-3-nitrophenyl) (pyridin-4-yl) methanone (CNPM) with quadruple functional groups is introduced into the ZnSO4 electrolyte to reshape the interface between ZMA and electrolyte and change the solvation structure of Zn2+ . Density functional theory (DFT) calculations manifest that the ─C═O, ─Cl, ─C═N─, and ─NO2 functional groups of CNPM interact with metallic Zn simultaneously and adsorb on the ZMA surface in a parallel arrangement manner, thus forming a water-poor IHL and creating well-arranged ion transportation channels. Furthermore, theoretical calculations and experimental results demonstrate that CNPM absorbed on the Zn anode surface can serve as zincophilic sites for inducing uniform Zn deposition along the (002) plane. Benefiting from the synergistic effect of these functions, the dendrite growth and parasitic reactions are suppressed significantly. As a result, ZMA exhibits a long cycle life (2900 h) and high coulombic efficiency (CE) (500 cycles) in the ZnSO4 +CNPM electrolyte.

Uniform self-rectifying resistive random-access memory based on an MXene-TiO2 Schottky junction.

For filamentary resistive random-access memory (RRAM) devices, the switching behavior between different resistance states usually occurs abruptly, while the random formation of conductive filaments usually results in large fluctuations in resistance states, leading to poor uniformity. Schottky barrier modulation enables resistive switching through charge trapping/de-trapping at the top-electrode/oxide interface, which is effective for improving the uniformity of RRAM devices. Here, we report a uniform RRAM device based on a MXene-TiO2 Schottky junction. The defect traps within the MXene formed during its fabricating process can trap and release the charges at the MXene-TiO2 interface to modulate the Schottky barrier for the resistive switching behavior. Our devices exhibit excellent current on-off ratio uniformity, device-to-device reproducibility, long-term retention, and endurance reliability. Due to the different carrier-blocking abilities of the MXene-TiO2 and TiO2-Si interface barriers, a self-rectifying behavior can be obtained with a rectifying ratio of 103, which offers great potential for large-scale RRAM applications based on MXene materials.

Quasiparticle interference and nonsymmorphic effect on a floating band surface state of ZrSiSe.

Non-symmorphic crystals are generating great interest as they are commonly found in quantum materials, like iron-based superconductors, heavy-fermion compounds, and topological semimetals. A new type of surface state, a floating band, was recently discovered in the nodal-line semimetal ZrSiSe, but also exists in many non-symmorphic crystals. Little is known about its physical properties. Here, we employ scanning tunneling microscopy to measure the quasiparticle interference of the floating band state on ZrSiSe (001) surface and discover rotational symmetry breaking interference, healing effect and half-missing-type anomalous Umklapp scattering. Using simulation and theoretical analysis we establish that the phenomena are characteristic properties of a floating band surface state. Moreover, we uncover that the half-missing Umklapp process is derived from the glide mirror symmetry, thus identify a non-symmorphic effect on quasiparticle interferences. Our results may pave a way towards potential new applications of nanoelectronics.