Xiaoming Xie

• Chinese Academy of Sciences

Phototoxicity poses a substantial challenge in photodynamic therapy, resulting in intolerable skin damage, visual impairment, and reduced quality of life. Current coping strategies, primarily focus on avoiding inappropriate photoactivation and developing targeted photosensitizers, have not effectively addressed this problem. Hence, this study aims...

Investigating proton transport at the interface in an excited state facilitates the mechanistic investigation and utilization of nanomaterials. However, there is a lack of suitable tools for in-situ and interfacial analysis. Here we addresses this gap by in-situ observing the proton transport of graphene quantum dots (GQDs) in an excited state thro...

Due to isotropic superconducting properties and the lack of breaking of inversion symmetry for conventional s‐wave superconductors, a nonreciprocal superconducting diode effect is absent. Recently, a series of superconducting structures, including superconducting superlattice, and quantum‐material‐based superconducting Josephson junction, have exhi...

2D magnetic semiconductors exhibit great potential for next‐generation spintronics, but realizing their full capabilities has been hindered by the low Curie temperatures (Tc) below 50 K observed in current materials. Here, a new mechanism to substantially enhance the Tc of 2D semiconducting materials through incorporating both in‐plane and out‐of‐p...

We have developed and fabricated a LTS SQUID gradiometer using Direct writing lithography technology. A niobium thin-film first-order pickup coil is connected to the input coil of a SQUID current sensor via superconducting niobium wire bonds. Both, the fine-scale Josephson junctions and the large-scale pickup coil, are fabricated by this technology...

Rapid detection and discrimination of single photons are pivotal in various applications, such as deep-space laser communication, high-rate quantum key distribution, and optical quantum computation. However, conventional single-photon detectors (SPDs), including semiconducting and recently developed superconducting detectors, have limited detection...

Quantum phase slip (QPS) is an important effect that occurs in one-dimensional (1D) or quasi-1D superconducting (SC) materials. Due to the extremely high requirements on the uniformity and quality of SC nanowires, it is currently very challenging to obtain repeatable and controllable QPS devices. Here, we report a systematic study of the QPS effect...

For complex SQUID biomagnetic systems, such as multi-channel magnetoneurography, channel crosstalk has been studied and solved to some extent, but the crosstalk effects of superconductors themselves are rarely considered. In this paper, the crosstalk characteristics of superconducting coils induced by electromagnetic mutual inductance and Meissner...

Tumor-derived circulating exosomes (TDEs) are being pursued as informative and noninvasive biomarkers. However, quantitatively detecting TDEs is still challenging. Herein, we constructed a DNA tetrahedral-structured probe (TSP)-mediated microfluidic magnetic detection system (μFMS) to provide a rapid and sensitive platform for analyzing TDEs. CD63...

Single flux quantum (SFQ) circuitry is a promising candidate for a scalable and integratable cryogenic quantum control system. However, the operation of SFQ circuits introduces nonequilibrium quasiparticles (QPs), which are a significant source of qubit decoherence. In this study, we investigate QP behavior in a superconducting quantum-classical hy...

Single flux quantum (SFQ) circuitry is a promising candidate for a scalable and integratable cryogenic quantum control system. However, the operation of SFQ circuits introduces non-equilibrium quasiparticles (QPs), which are a significant source of qubit decoherence. In this study, we investigate QP behavior in a superconducting quantum-classical h...

Different from hexagonal boron nitride (hBN) sheets, the bandgap of hBN nanoribbons (BNNRs) can be changed by spatial/electrostatic confinement. It has been predicted that a transverse electric field can narrow the bandgap and even cause an insulator-metal transition in BNNRs. However, experimentally introducing an overhigh electric field across th...

Graphene sitting on hexagonal boron nitride (h-BN) always exhibits excellent electrical properties. And the properties of graphene on h-BN are often dominated by its domain size and boundaries. Chemical vapor deposition (CVD) is a promising approach to achieve large size graphene crystal. However, the CVD growth of graphene on h-BN still faces chal...

The hydration of perfluorinated sulfonic-acid (PFSA) ionomers is the most important phenomenon that determines their transport and electrical properties. To bridge the gap between the macroscopic electrical properties and the microscopic water-uptake mechanism, we investigated the hydration process of a Nafion membrane using ambient-pressure X-ray...

Mass Production of Graphene In article number 2203124, Ningzhen Wang, Guqiao Ding, Qingkai Yu, Xiaoming Xie, and co‐workers summarize and discuss the mass production of graphene with the assistance of bubbles. As a new tool, the usage of bubbling makes a big difference in multiple aspects of graphene production. This review sheds light on the intro...

Phase Change Cells In article number 2202222 by Haomin Wang, Zhitang Song, and co‐workers, edge of graphene ribbons is used to address phase change materials. The highly scaled memory cells approach the extreme scaling limits of phase change materials technology, achieving ultralow power consumption, high programming speeds, outstanding low/high re...

The molten salts can be used as media for hydrocarbon pyrolysis owing to their excellent thermal properties, fluidity, and ease of products separation. The bubbling of hydrocarbon gases through the molten salts is an effective approach for exploiting the comprehensive advantages of the molten salts. However, the catalytic capability of the molten s...

The large‐scale industrial applications of graphene highly depend on its mass production with efficiency (high‐yield, time‐saving, and low‐cost) and controllability (high‐quality, safe, and environmentally friendly). However, this requirement can hardly be satisfied by incumbent chemical exfoliation methods exploiting liquid–solid interactions. Rec...

Ultra‐large graphene oxide (ULGO) is one of the most important graphene derivates because of its processability in constructing various macrostructures with unique properties. However, existing oxidation–exfoliation technologies are limited in the available size range, structure controllability, and preparation efficiency of ULGO by the slow oxidan...

Nonvolatile phase change random access memory (PCRAM) is regarded as one of promising candidates for emerging mass storage in the era of Big Data. However, relatively high programming energy hurdles the further reduction of power consumption in PCRAM. Utilizing narrow edge-contact of graphene can effectively reduce the active volume of phase change...

Nonvolatile phase‐change random access memory (PCRAM) is regarded as one of the promising candidates for emerging mass storage in the era of Big Data. However, relatively high programming energy hurdles the further reduction of power consumption in PCRAM. Utilizing narrow edge‐contact of graphene can effectively reduce the active volume of phase ch...

Single‐photon emitters (SPEs) can play an important role in future quantum optics. Hexagonal boron nitride (h‐BN), a layered insulator (bandgap ≈6 eV), is a promising candidate for next‐generation SPEs because of its chemical and thermal stability and high brightness at room temperature. In this review, the microstructures (atomic defects, deformat...

High quality superconducting thin films are the basis for the application of superconducting devices. Here, we report on the film growth and superconducting properties of Ta films. The films were grown by the pulsed laser deposition technique on the α-Al2O3 substrates. It is found that, with the increase of the film thickness from 20 nm to 61 nm, b...

Perfluoro‐tert‐butylation reaction has long remained a challenging task. We now report the use of 1,1‐dibromo‐2,2‐bis(trifluoromethyl)ethylene (DBBF) as a practical reagent for perfluoro‐tert‐butylation reactions for the first time. Through a consecutive triple‐fluorination process with DBBF and CsF, the (CF3)3C⁻ species can be liberated and observ...

Perfluoro- tert -butylation reaction has long remained a challenging task. We now report the use of 1,1-dibromo-2,2bis(trifluoromethyl)ethylene (DBBF) as a practical reagent for perfluoro- tert -butylation reactions for the first time. Through a consecutive triple-fluorination process with DBBF and CsF, the (CF 3 ) 3 C − species can be liberated an...

Graphene nanoribbons (GNRs) are a family of one-dimensional (1D) materials carved from graphene lattice. GNRs possess high mobility and current carrying capability, sizable bandgap, and versatile electronic properties tailored by the orientations and open edge structures. These unique properties make GNRs promising candidates for prospective electr...

As a two-dimensional carbon based semiconductor, C3N acts as a promising material in many application areas. However, the basic physical properties such as Raman spectrum properties of C3N is still not clear. In this paper, we clarify the Raman spectrum properties of multilayer C3N. Moreover, the stacking driven Raman spectra change of multilayer C...

The development of high-performance direct-current (DC) nanogenerators with good flexibility in wearable devices has always been a major challenge. A potential solution is developing the flexible Schottky nanogenerators to output DC power by introducing Schottky interfaces between metals and flexible semiconductors to directionally transfer the mec...

To better understand the working principles of Superconducting Quantum Interference Device (SQUID) direct readout schemes, which work in different bias and amplifier modes with different internal feedback schemes, we present the complete circuit analyses on SQUID small-signal model. SQUID bias and amplifier circuits are analyzed using SQUID Theveni...

Graphene nanoribbons (GNRs) are a family of one-dimensional (1D) materials with a graphitic lattice structure. GNRs possess high mobility and current-carrying capability, sizeable bandgap and versatile electronic properties, which make them promising candidates for quantum electronic applications. In the past 5 years, progress has been made towards...

Many of graphene’s industrial applications such as electromagnetic interference (EMI) shielding demand efficient fabrication of high-quality graphene in large scale. Existing electrochemical exfoliation is a trade-off but never an ideal solution in this regard. Herein, we propose a delocalized electrochemical exfoliation (DEE) strategy to revolutio...

If a bulk material can withstand a high load without any irreversible damage (such as plastic deformation), it is usually brittle and can fail catastrophically1,2. This trade-off between strength and fracture toughness also extends into two-dimensional materials space3,4,5. For example, graphene has ultrahigh intrinsic strength (about 130 gigapasca...

Hexagonal boron nitride (h-BN) is an exciting two dimensional dielectric due to its atomic flatness, free of dangling bonds, exceptional thermal and chemical stabilities. Here we report a method of silicon-assisted synthesis of monolayer h-BN on germanium (Ge) by chemical vapor deposition. The silicon atoms dissolve into Ge (110) and promote the gr...

The development of ultra-sensitive methods for detecting anions is limited by their low charge to radius ratios, microenvironment sensitivity, and pH sensitivity. In this paper, a magnetic sensor is devised that exploits the controllable and selective coordination that occurs between a magnetic graphene quantum dot (GQD) and fluoride anion (F–). Th...

Superconducting nanowire single-photon detectors (SNSPDs) have attracted remarkable interest for visible and near-infrared single-photon detection due to their outstanding performance. However, conventional SNSPDs are generally used as binary photon-counting detectors. Another important characteristic of light, i.e., polarization, which can provide...

Generally, a superconducting nanowire single-photon detector (SNSPD) is composed of wires with a typical width of ~100 nm. Recent studies have found that superconducting stripes with a micrometer-scale width can also detect single photons. Compared with the SNSPD covering the same area, the superconducting microstrip single-photon detector (SMSPD)...

The integrated in-plane growth of graphene nanoribbons (GNRs) and hexagonal boron nitride (h-BN) could provide a promising route to achieve integrated circuitry of atomic thickness. However, fabrication of edge-specific GNRs in the lattice of h-BN still remains a significant challenge. Here we developed a two-step growth method and successfully ach...

More than 50 years ago superconducting quantum interference devices (SQUIDs) were invented. Since then many applications opened up. Already in a 1980 workshop (Weinstock and Overton 1981 SQUID Applications to Geophysics (Society of Exploration Geophysicists)) the application of SQUIDs in geosciences was reviewed. The fabrication and cooling technol...

Electrochemical exfoliation of graphite stands out as a promising alternative to the existing methods for scalable graphene fabrication. However, factors governing the electrochemical process and the underlying mechanism are complex and how to effectively control the exfoliation process is far from completely clear despite many attempts in previous...

Direct current superconducting quantum interference device (dc SQUID) can be regarded as a hybrid system with two nonlinear Josephson currents driving a linear network consists of conventional resistors (R), inductors (L), and capacitors (C). There must be LC resonances inside the SQUID loop with influences on its static current-voltage characteris...

Practical superconducting quantum interference devices (SQUIDs) have been developed into multiloop hybrid electric circuits with Josephson junctions and normal elements such as resistor, inductor and capacitor. To find a common circuit analysis and simulation method for different types of SQUID hybrid circuits consist of both superconducting and no...

We report an in-depth investigation on the out-of-plane lower critical field H c1 of the KCa2(Fe1-x Co x )4As4F2 (12442-type, x = 0, 0.1). The multi-gap feature is revealed by the kink in the temperature-dependent H c1(T) curve for the two samples with different doping levels. Based on a simplified two-gap model, the magnitudes of the two gaps are...

Early warning of tumor formation is crucial for the classification, treatment, and prognosis of tumor patients. Here, a new strategy is reported, aimed at realizing this goal based on imaging aerobic glycolysis processes using nitrogen‐doped carbon dots (N‐CDs) as fluorescent probes. The intensity of the photoluminescence emitted by the N‐CDs is sp...

It has been found that when SQUID magnetometers operate in a geomagnetic field environment , its output will occasionally show small momentary jumps with the change of the external magnetic field, which seriously affects the measurement accuracy of the geomagnetic field and needs to be eliminated. A magnetic flux jump model called the Parasitic Sup...

Superconducting nanowire single-photon detector (SNSPD) with near-unity system efficiency is a key enabling, but still elusive, technology for numerous quantum fundamental theory verifications and quantum information applications. The key challenge is to have both a near-unity photon-response probability and absorption efficiency simultaneously for...

Superconducting devices such as superconducting quantum interference devices, superconductor nanowire single photon detectors, and superconducting quantum chips have unique performances not available in conventional semiconductor devices. However, most of the superconducting devices are fabricated on rigid substrates consequently limiting applicati...

Wafer-scale single-crystal graphene with high carrier mobility is essential as a promising channel material for the next-generation two-dimensional nanoelectronics. However, direct synthesis of wafer-scale single-crystal graphene on complementary metal oxide semiconductor (CMOS) compatible substrates still remains a challenge. Herein, we demonstrat...

Superconducting nanowire single-photon detector (SNSPD) with near-unity system efficiency is a key enabling, but still elusive technology for numerous quantum fundamental theory verifications and quantum information applications. The key challenge is to have both a near-unity photon-response probability and absorption efficiency simultaneously for...

The integrated inplane growth of two dimensional materials with similar lattices, but distinct electrical properties, could provide a promising route to achieve integrated circuitry of atomic thickness. However, fabrication of edge specific GNR in the lattice of hBN still remains an enormous challenge for present approaches. Here we developed a two...

Disorder-induced Griffiths singularity of quantum phase transition (QPT) is a crucial issue in 2D superconductors (2DSC). In a superconducting system, the strength of disorder is found to be associated with the vortex pinning energy, which is closely related to the quantum Griffiths singularity; however, a direct study to elucidate the role of vort...

Flux modulated static current-voltage characteristics are the basis of DC SQUID being the flux-to-voltage convertor utilized in high-performance magnetic field measurement systems. Those static behaviors are the results of the internal quantum interference between two Josephson junctions. However, the interferometric working principle and the inter...

In ultra-low-field magnetic resonance imaging (ULF MRI) working in the micro-tesla magnetic field range, the superconducting quantum interference device (SQUID) as the signal detector is very susceptible to electromagnetic interference (EMI) so that the system normally works in a shielded room. However, the leakage of EMI in the shielded room may s...

In this paper, we present an overview of the devolvement of niobium nitride (NbN)-based superconducting nanowire single-photon detector (SNSPD) array for applications in SIMIT. These applications include high-speed interleaved nanowire arrays for optical quantum communication, large-active-area arrays for light detection and ranging (LIDAR), and fr...

Superconducting nanowire single-photon detectors (SNSPDs) have attracted remarkable interest for visible and near infrared single-photon detection, owing to their outstanding performance. Conventional SNSPDs are generally used as binary photon-counting detector. Another important characteristic of light, i.e., polarization, has not been resolved us...

To promote the adaptability of the practical Magnetocardiography (MCG) system working in unshielded environment, the SQUID readout electronics is required to improve its stability and the Electromagnetic Compatibility (EMC). It should be low-drift to the variation of cryogenic liquid level in long-time running, avoid Electromagnetic Interference (E...

Charge carriers in graphene exhibit distinct characteristics from those in other two-dimensional materials because of their chiral nature. Additionally, multiple Dirac cones that emerge in graphene superlattices have been regarded as an interesting point in condensed-matter physics in recent years. Here, we report an investigation of the magneto-co...

To implement a Flux Quanta Counting (FQC) scheme in the wide range magnetic field measurement using Superconducting Quantum Interference Device (SQUID), we present a SQUID Proportional Feedback Amplifier (PFA) circuit. It is a simplified version of the direct readout Flux-Locked Loop (FLL) electronics without integrator. It achieved a periodically...

The development of photonic quantum information technologies requires research on the properties of optical adhesives at cryogenic temperatures. In the process of developing microfiber (MF)-coupled superconducting nanowire single-photon detectors (SNSPDs), we invented a cryogenic-temperature refractive index (RI) measurement method based on a kind...

Multilayer hexagonal boron nitride (h-BN) is highly desirable as a dielectric substrate for the fabrication of two-dimensional (2D) electronic and optoelectronic devices. However, the controllable synthesis of multilayer h-BN in large areas is still limited in terms of crystallinity, thickness and stacking order. Here, we report a vapor–liquid–soli...

Recently, Bi2O2Se is discovered as a promising two-dimensional (2D) semiconductor for next generation electronics, due to its moderate bandgap size, high electron mobility and pronounced ambient stability. Meanwhile, it has been predicted that high quality Bi2O2Se-related heterostructures may possess exotic physical phenomena, such as piezoelectric...

Nonlinearity with multiple working points limits the practical applications of two-stage Superconducting Quantum Interference Device (SQUID) readout circuit which is promising for low noise performance. To solve this problem, we proposed a simple two-stage SQUID readout circuit with two conventional dc SQUIDs improved with proportional feedback sch...

High-efficiency superconducting nanowire single-photon detectors (SNSPDs), which have numerous applications in quantum information systems, function by using the optical cavity and the ultrasensitive photon response of their ultra-thin superconducting nanowires. However, the wideband response of superconducting nanowires is limited due to the reson...

To better understand working principles of Superconducting Quantum Interference Device (SQUID) direct readout schemes which are working in different bias and amplifier modes with different internal feedback schemes, we present the complete circuit analyses based on SQUID small signal model. SQUID bias and amplifier circuits are analyzed using SQUID...

In article number 1903732, Peng He, Guqiao Ding, and co‐workers prepare a porous composite fiber composed of graphene networks and decorated polymer nanoballs for wearable strain sensors. With an optimized graphene‐polymer interface area, these fibers show excellent sensitivity, a low detection limit, and long durability to small strains, which ena...

A superconducting nanowire single-photon detector (SNSPD) has played a significant role in numerous applications for visible and near-infrared photon detection. SNSPDs with high system detection efficiency (SDE greater than 90%) would enable remarkable experiments in quantum information processing. Currently, niobium nitride- (NbN) based SNSPDs are...

In this work, we report a large-active-area multispectral superconducting nanowire single-photon detector for free-space applications. The detector is realized by fabricating NbTiN nanowire with an active area of 35 µm diameter on two serially connected dielectric mirrors that can simultaneously and efficiently detect single photons at the three ty...

A SQUID planar gradiometer is an extremely sensitive sensor for magnetic gradient measurements. It has been shown to have potential applications for aeromagnetic detection. The major challenge when operating an aeromagnetic SQUID system in actual environment is the motion noise, including the inherent response resulting from gradiometer imbalance a...

To implement wide range measurement using direct current Superconducting Quantum Interference Device (dc SQUID), we presented a simple two-terminal SQUID amplifier consists of a shunt resistor and a conventional SQUID in series with feedback coil. Only two terminals are led out with coaxial cable for high speed and low heat loss. Periodically repea...

Layered honeycomb compound SrRu2O6 has drawn great attentions because of the unconventional magnetism with a rather high Ne′el temperature and small ordered moments. Here we report the optimization of synthesis parameters for SrRu2O6 samples based on the hydrothermal method. The synthesis conditions were tuned carefully in terms of reaction tempera...

Large active-area superconducting nanowire single-photon detectors (SNSPDs) coupled with multimode fibers (MMFs) can provide high light-gathering capacity, which is essential for free-space detection applications in photon-starved regimes. However, MMF-coupled SNSPDs often suffer from large system dark count rates (DCRsys) over kHz due to blackbody...

Broadband photon detectors are a key enabling technology for various applications such as spectrometers, light detection and ranging. In this work, we report on an ultra-broadband single-photon detector based on a microfiber (MF)-coupled superconducting nanowires structure operating in the spectral range from visible to near-infrared light. The MF-...

The success in the synthesis of wafer-size single-crystal graphene enables a tremendous breakthrough in the development of graphene-based devices. Understanding the growth mechanism is essential for the design of suitable substrates to meet the demand of various applications. Here, we investigate the detailed growth process of the monolayer single-...

Low-temperature specific heat (SH) is measured on the 1111-type CaFe_0.88Co_0.12AsF single crystals under different magnetic fields. A clear SH jump with the height ΔC/T|_Tc = 10.4 mJ/mol K² was observed at the superconducting transition temperature T_c. The electronic SH coefficient Δγ(B) increase...

Low field (LF) nuclear magnetic resonance (NMR) shows potential advantages to study pure heteronuclear J-coupling and observe the fine structure of matter. Power-line harmonics interferences and fixed-frequency noise peaks might introduce discrete noise peaks into the LF-NMR spectrum in an open environment or in a conductively shielded room, which...

Wearable textile strain sensors that can perceive and respond to human stimuli are an essential part of wearable electronics. Yet, the detection of subtle strains on the human body suffers from the low sensitivity of many existing sensors. Generally, the inadequate sensitivity originates from the strong structural integrity of the sensors because t...

Superconducting nanowire single-photon detectors (SNSPDs) with both an ultra-large-active area and a high count rate (CR) are challenging from the design and fabrication. Here, we develop a NbN SNSPD with a circular active area of 300 μm-in-diameter and use multiple approaches to boost the maximal count rate (MCR). This large-active-area SNSPD is d...

Two-dimensional (2D) layered Bi2O2Se is provoking immense interests owing to its great potential for next generation electronics, due to its high electron mobility, moderate bandgap size and excellent environmental stability. Meanwhile, it has been predicted that high quality Bi2O2Se-related heterostructures may possess exotic physical phenomena, s...

Low-temperature specific heat (SH) is measured on the 1111-type CaFe_{0.88}Co_{0.12}AsF single crystals under different magnetic fields. A clear SH jump with the height \Delta C/T|_Tc = 10.4 mJ/mol K^2 was observed at the superconducting transition temperature T_c. The electronic SH coefficient \Delta\gamma (B) increases linearly with the field bel...

Atomically thin hexagonal boron nitride (h-BN) is often regarded as an elastic film that is impermeable to gases. The high stabilities in thermal and chemical properties allow h-BN to serve as a gas barrier under extreme conditions.In this work, we demonstrate the isolation of hydrogen in bubbles of h-BN via plasma treatment.Detailed characterizati...

To implement wide range measurement using direct current Superconducting Quantum Interference Device (dc SQUID), we presented a simple two-terminal SQUID amplifier consists of a shunt resistor and a conventional SQUID in series with feedback coil. Only two terminals are led out with coaxial cable for high speed and low heat loss. Periodically repea...