Topological Transition of Superconductivity in Dirac Semimetal Nanowire Josephson Junctions.

We report the topological transition by gate control in a Cd_{3}As_{2} Dirac semimetal nanowire Josephson junction with diameter of about 64 nm. In the electron branch, the quantum confinement effect enforces the surface band into a series of gapped subbands and thus nontopological states. In the hole branch, however, because the hole mean free path is smaller than the nanowire perimeter, the quantum confinement effect is inoperative and the topological property maintained.

Reducing Electronic Transport Dimension to Topological Hinge States by Increasing Geometry Size of Dirac Semimetal Josephson Junctions.

The notion of topological phases has been extended to higher-order and has been generalized to different dimensions. As a paradigm, Cd_{3}As_{2} is predicted to be a higher-order topological semimetal, possessing three-dimensional bulk Dirac fermions, two-dimensional Fermi arcs, and one-dimensional hinge states. These topological states have different characteristic length scales in electronic transport, allowing one to distinguish their properties when changing sample size.

Topological Semimetal Nanostructures: From Properties to Topotronics.

Characterized by bulk Dirac or Weyl cones and surface Fermi-arc states, topological semimetals have sparked enormous research interest in recent years. The nanostructures, with large surface-to-volume ratio and easy field-effect gating, provide ideal platforms to detect and manipulate the topological quantum states. Exotic physical properties originating from these topological states endow topological semimetals attractive for future topological electronics (topotronics).

Fermi-arc supercurrent oscillations in Dirac semimetal Josephson junctions.

One prominent hallmark of topological semimetals is the existence of unusual topological surface states known as Fermi arcs. Nevertheless, the Fermi-arc superconductivity remains elusive. Here, we report the critical current oscillations from surface Fermi arcs in Nb-Dirac semimetal CdAs-Nb Josephson junctions.

4π-Periodic Supercurrent from Surface States in Cd_{3}As_{2} Nanowire-Based Josephson Junctions.

The combination of superconductivity and surface states in Dirac semimetal can produce a 4π-periodic supercurrent in a Josephson junction configuration, which can be revealed by the missing of odd Shapiro steps (especially the n=1 step). However, the suppression of the n=1 step is also anticipated in the high-power oscillatory regime of the ordinary 2π-periodic Josephson effect, which is irrelevant to the 4π-periodic supercurrent. Here, in order to identify the origin of the suppressed n=1 step, we perform the measurements of radio frequency irradiation on Nb-Dirac semimetal Cd_{3}As_{2} nanowire-Nb junctions with continuous power dependence at various frequencies.

Astrocyte Elevated Gene 1 (AEG-1) Acts as a Promoter Gene in Clear Cell Renal Cell Carcinoma Cell Growth and Metastasis.

BACKGROUND Clear cell renal cell carcinoma (ccRCC) is usually incurable once it progresses to metastatic stage. Hence, in-depth investigations to reveal the precise molecular mechanisms behind the metastasis of ccRCC are required to improve the therapeutic outcome of ccRCC. MATERIAL AND METHODS The level of astrocyte elevated gene 1 (AEG-1) in ccRCC tissues and cell lines was determined by quantitative real-time PCR (qRT-PCR) assay.

Quantification of light-enhanced ionic transport in lead iodide perovskite thin films and its solar cell applications.

Ionic transport in organometal halide perovskites is of vital importance because it dominates anomalous phenomena in perovskite solar cells, from hysteresis to switchable photovoltaic effects. However, excited state ionic transport under illumination has remained elusive, although it is essential for understanding the unusual light-induced effects (light-induced self-poling, photo-induced halide segregation and slow photoconductivity response) in organometal halide perovskites for optoelectronic applications. Here, we quantitatively demonstrate light-enhanced ionic transport in CHNHPbI over a wide temperature range of 17-295 K, which reveals a reduction in ionic transport activation energy by approximately a factor of five (from 0.

Ultrafast Broadband Photodetectors Based on Three-Dimensional Dirac Semimetal CdAs.

Photodetection with extreme performances in terms of ultrafast response time, broad detection wavelength range, and high sensitivity has a wide range of optoelectronic and photonic applications, such as optical communications, interconnects, imaging, and remote sensing. Graphene, a typical two-dimensional Dirac semimetal, has shown excellent potential toward a high-performance photodetector with high operation speed, broadband response, and efficient carrier multiplications benefiting from its linear dispersion band structure with a high carrier mobility and zero bandgap. As the three-dimensional analogues of graphene, Dirac semimetal CdAs processes all advantages of graphene as a photosensitive material but potentially has stronger interaction with light as a bulk material and thus enhanced responsivity.

Strain-Gradient Modulated Exciton Emission in Bent ZnO Wires Probed by Cathodoluminescence.

Photoelectrical properties of semiconductor nanostructures are expected to be improved significantly by strain engineering. Besides the local strain, the strain gradient is promising to tune the luminescence properties by modifying the crystal symmetry. Here, we report the investigation of strain-gradient induced symmetry-breaking effect on excitonic states in pure bending ZnO microwires by high spatial-resolved cathodoluminescence at low temperature of 80 K.

Anti-cancer effect of ursolic acid activates apoptosis through ROCK/PTEN mediated mitochondrial translocation of cofilin-1 in prostate cancer.

Ursolic acid is a type of pentacyclic triterpene compound with multiple pharmacological activities including cancer resistance, protection from liver injury, antisepsis, anti-inflammation and antiviral activity. The present study aimed to investigate the anticancer effect of ursolic acid. Ursolic acid activates cell apoptosis and its pro-apoptotic mechanism remains to be fully elucidated.

Aharonov-Bohm oscillations in Dirac semimetal Cd3As2 nanowires.

Three-dimensional Dirac semimetals, three-dimensional analogues of graphene, are unusual quantum materials with massless Dirac fermions, which can be further converted to Weyl fermions by breaking time reversal or inversion symmetry. Topological surface states with Fermi arcs are predicted on the surface and have been observed by angle-resolved photoemission spectroscopy experiments. Although the exotic transport properties of the bulk Dirac cones have been demonstrated, it is still a challenge to reveal the surface states via transport measurements due to the highly conductive bulk states.

Giant negative magnetoresistance induced by the chiral anomaly in individual Cd3As2 nanowires.

Dirac electronic materials beyond graphene and topological insulators have recently attracted considerable attention. Cd3As2 is a Dirac semimetal with linear dispersion along all three momentum directions and can be viewed as a three-dimensional analogue of graphene. By breaking of either time-reversal symmetry or spatial inversion symmetry, the Dirac semimetal is believed to transform into a Weyl semimetal with an exotic chiral anomaly effect, however the experimental evidence of the chiral anomaly is still missing in Cd3As2.

Zeeman effect on surface electron transport in topological insulator Bi2Se3 nanoribbons.

Topological insulators have exotic surface states that are massless Dirac fermions, manifesting special magnetotransport properties, such as the Aharonov-Bohm effect, Shubnikov-de Haas oscillations, and weak antilocalization effects. In the surface Dirac cone, the band structures are typically closely related to the p-orbitals and possess helical orbital texture. Here we report on the tunability of the transport properties via the interaction between the magnetic field and the spin-orbital angular momentum of the surface states in individual Bi2Se3 nanoribbons.

Lateral graphene p-n junctions formed by the graphene/MoS₂ hybrid interface.

Graphene/two-dimensional (2D) semiconductor heterostructures have been demonstrated to possess many advantages for electronic and optoelectronic devices. However, there are few reports about the utilization of a 2D semiconductor monolayer to tune the properties of graphene. Here, we report the fabrication and characterization of graphene p-n junctions based on graphene/MoS2 hybrid interfaces.

Gate Modulation of Graphene-ZnO Nanowire Schottky Diode.

Graphene-semiconductor interface is important for the applications in electronic and optoelectronic devices. Here we report the modulation of the electric transport properties of graphene/ZnO nanowire Schottky diode by gate voltage (Vg). The ideality factor of the graphene/ZnO nanowire Schottky diode is ~1.

Magnetotransport across the metal-graphene hybrid interface and its modulation by gate voltage.

The graphene-metal contact is very important for optimizing the performance of graphene based electronic devices. However, it is difficult to probe the properties of the graphene/metal interface directly via transport measurements in traditional graphene lateral devices, because the dominated transport channel is graphene, not the interface. Here, we employ the Au/graphene/Au vertical and lateral hybrid structure to unveil the metal-graphene interface properties, where the transport is dominated by the charge carriers across the interface.

Vertically architectured stack of multiple graphene field-effect transistors for flexible electronics.

Vertically architectured stack of multiple graphene field-effect transistors (GFETs) on a flexible substrate show great mechanical flexibility and robustness. The four GFETs are integrated in the vertical direction, and dually gated GFETs with graphene channel, PMMA dielectrics, and graphene gate electrodes are realized.

Topological surface state enhanced photothermoelectric effect in Bi2Se3 nanoribbons.

The photothermoelectric effect in topological insulator Bi2Se3 nanoribbons is studied. The topological surface states are excited to be spin-polarized by circularly polarized light. Because the direction of the electron spin is locked to its momentum for the spin-helical surface states, the photothermoelectric effect is significantly enhanced as the oriented motions of the polarized spins are accelerated by the temperature gradient.

Magnetic moments in graphene with vacancies.

Vacancies can induce local magnetic moments in graphene, paving the way to make magnetic functional graphene. Due to the interaction between magnetic moments and conduction carriers, the magnetotransport properties of graphene can be modulated. Here, the effects of vacancy induced magnetic moments on the electrical properties of graphene are studied via magnetotransport measurements and spin-polarized density functional theory calculations.

Fabrication and electrical properties of stacked graphene monolayers.

We develop a simple method to fabricate the two-stacked graphene monolayers and investigate the electronic transport in such a system. The independence of the two graphene monolayers gives rise to the asymmetric resistance-gate voltage curves and an eight-fold degeneracy of Landau level. The position of the maximum resistance of the transfer curves shifts towards higher gate voltage with increasing magnetic field, which is attributed to the magnetic field induced interlayer decoupling of the stacked graphene monolayers.

High-mobility Bi2Se3 nanoplates manifesting quantum oscillations of surface states in the sidewalls.

Magnetotransport measurements of topological insulators are very important to reveal the exotic topological surface states for spintronic applications. However, the novel properties related to the surface Dirac fermions are usually accompanied by a large linear magnetoresistance under perpendicular magnetic field, which makes the identification of the surface states obscure. Here, we report prominent Shubnikov-de Haas (SdH) oscillations under an in-plane magnetic field, which are identified to originate from the surface states in the sidewalls of topological insulator Bi2Se3 nanoplates.

Vertical graphene spin valve with Ohmic contacts.

Evident spin valve signals are observed in Co/graphene/Co sandwich structures with both monolayer and two-layer graphene stacks at temperatures from 1.5 K to 300 K. All the devices demonstrate linear current-voltage curves, indicating that an Ohmic property is dominating rather than a tunneling effect.

Layer-by-layer assembly of vertically conducting graphene devices.

Graphene has various potential applications owing to its unique electronic, optical, mechanical and chemical properties, which are primarily based on its two-dimensional nature. Graphene-based vertical devices can extend the investigations and potential applications range to three dimensions, while interfacial properties are crucial for the function and performance of such graphene vertical devices. Here we report a general method to construct graphene vertical devices with controllable functions via choosing different interfaces between graphene and other materials.