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When a topological insulator is made into a nanowire, the interplay between topology and size quantization gives rise to peculiar one-dimensional states whose energy dispersion can be manipulated by external fields. In the presence of proximity-induced superconductivity, these 1D states offer a tunable platform for Majorana zero modes. While the existence of such peculiar 1D states has been experimentally confirmed, the realization of robust proximity-induced superconductivity in topological-insulator nanowires remains a challenge. Here, we report the realization of superconducting topological-insulator nanowires based on (Bi 1− x Sb x ) 2 Te 3 (BST) thin films. When two rectangular pads of palladium are deposited on a BST thin film with a separation of 100–200 nm, the BST beneath the pads is converted into a superconductor, leaving a nanowire of BST in-between. We found that the interface is epitaxial and has a high electronic transparency, leading to a robust superconductivity induced in the BST nanowire. Due to its suitable geometry for gate-tuning, this platform is promising for future studies of Majorana zero modes. Topological insulator nanowires are interesting because, in the presence of superconductivity, they may host elusive Majorana fermions. Here, superconductivity in (Bi 1− x Sb x ) 2 Te 3 topological-insulator nanowires is realized by using palladium diffusion, providing a tunable platform for Majorana zero modes.

Intra‐tumoral microbiota, which is a potential component of the tumor microenvironment (TME), has been emerging as a key participant and driving factor in cancer. Previously, due to technical issues and low biological content, little was known about the microbial community within tumors. With the development of high‐throughput sequencing technology and molecular biology techniques, it has been demonstrated that tumors harbor highly heterogeneous symbiotic microbial communities, which affect tumor progression mechanisms through various pathways, such as inducing DNA damage, activating carcinogenic pathways, and inducing an immunesuppressive environment. Faced with the harmful microbial communities in the TME, efforts have been made to develop new technologies specifically targeting the microbiome and tumor microecology. Given the success of nanotechnology in cancer diagnosis and treatment, the development of nanotechnology to regulate microscale and molecular‐scale interactions occurring in the microbiome and tumor microecology holds promise for providing new approaches for cancer therapy. This article reviews the latest progress in this field, including the microbial community within tumors and its pro‐cancer mechanisms, as well as the anti‐tumor strategies targeting intra‐tumoral microorganisms using nanotechnology. Additionally, this article delivers prospects for the potential clinical significance and challenges of anti‐tumor strategies against intra‐tumoral microorganisms. Intra‐tumoral microbiota, which is a potential component of the tumor microenvironment, has been emerging as a key participant and driving factor in cancer. This article reviews the latest progress in this field, including the microbial community within tumors and its pro‐cancer mechanisms, as well as the anti‐tumor strategies targeting intra‐tumoral microorganisms using nanotechnology. Additionally, this article provides prospects for the potential clinical significance and challenges of targeted anti‐tumor strategies against intra‐tumoral microorganisms.

The outbreak of monkeypox virus (MPXV) was declared a Public Health Emergency of International Concern (PHEIC) by the World Health Organization (WHO), and the zoonotic disease caused by viral infection was renamed as “Mpox” on November 28, 2022. Currently, there is no approved vaccine or specific antiviral treatment for Mpox, and a main preventive strategy against MPXV infection remains the smallpox vaccine. Although there was an emergency use authorization (EUA) of Brincidofovir and Tecovirimat for the clinical treatment of clade II Mpox, while Tecovirimat failed to reduce the duration of Mpox lesions among patients infected with clade I Mpox in the Democratic Republic of the Congo (DRC). Therefore, it is still an urgent need to develop an effective medication. This review aims to enhance the understanding of Mpox and contribute to its prevention and treatment strategies, it provides a systemic introduction of the biological and epidemiological characteristics of MPXV, the clinical feature and diagnosis of Mpox, as well as treatment and prevention strategies, which will improve the comprehension about MPXV and offer potential strategies for clinical treatment. The monkeypox virus (MPXV) has spread to many countries and caused thousands of infections all over the world. This review comprehensively introduces the biology, epidemiological characteristics of MPXV, and clinical manifestations of Mpox. The approaches for diagnosis, treatment, and prevention are also introduced, aiming to improve the general comprehension of Mpox.

In a nanowire (NW) of a three-dimensional topological insulator (TI), the quantum-confinement of topological surface states leads to a peculiar subband structure that is useful for generating Majorana bound states. Top-down fabrication of TINWs from a high-quality thin film would be a scalable technology with great design flexibility, but there has been no report on top-down-fabricated TINWs where the chemical potential can be tuned to the charge neutrality point (CNP). Here we present a top-down fabrication process for bulk-insulating TINWs etched from high-quality (Bi\\(_{1-x}\\)Sb\\(_{x}\\))\\(_2\\)Te\\(_3\\) thin films without degradation. We show that the chemical potential can be gate-tuned to the CNP and the resistance of the NW presents characteristic oscillations as functions of the gate voltage and the parallel magnetic field, manifesting the TI-subband physics. We further demonstrate the superconducting proximity effect in these TINWs, preparing the groundwork for future devices to investigate Majorana bound states.

Crossed Andreev reflection (CAR) is a nonlocal transport phenomenon that creates/detects Cooper-pair correlations between distant places. It is also the basis of Cooper-pair splitting to generate remote entanglement. Although CAR has been extensively studied in semiconductors proximity-coupled to a superconductor, it has been very difficult to observe it in a topological insulator (TI). Here we report the first observation of CAR in a proximitized TI nanowire (TINW). We performed local and nonlocal conductance spectroscopy on mesoscopic TINW devices in which superconducting (Nb) and metallic (Pt/Au) contacts are made on a bulk-insulating TINW. The local conductance detected a hard gap, accompanied by the appearance of Andreev bound states that can reach zero-bias, while a negative nonlocal conductance was occasionally observed upon sweeping the chemical potential, giving evidence for CAR. Surprisingly, the CAR signal was detected even over 1.5 \\(\\mu\\)m, which implies that pair correlations extend over a length scale much longer than the expected superconducting coherence length of either Nb or the proximitised TINW. Such a long-range CAR effect is possibly due to an intricate role of disorder in proximitized nanowires. Also, our 0.9-\\(\\mu\\)m device presented a decent Cooper-pair splitting efficiency of up to 0.5.

A Josephson diode passes current with zero resistance in one direction but is resistive in the other direction. While such an effect has been observed in several platforms, a large and tunable Josephson diode effect has been rare. Here we report that a simple device consisting of a topological-insulator (TI) nanowire side-contacted by superconductors to form a lateral Josephson junction presents a large diode effect with the efficiency \\(\\eta\\) reaching 0.3 when a parallel magnetic field \\(B_{||}\\) is applied. Interestingly, the sign and the magnitude of \\(\\eta\\) is found to be tunable not only by \\(B_{||}\\) but also by the back-gate voltage. This novel diode effect can be understood by modeling the system as a nano-SQUID, in which the top and bottom surfaces of the TI nanowire each form a line junction and \\(B_{||}\\) creates a magnetic flux to thread the SQUID loop. This model further shows that the observed diode effect is accompanied by the emergence of topological superconductivity in TI nanowire based Josephson junction.

Using the superconducting proximity effect for engineering a topological superconducting state in a topological insulator (TI) is a promising route to realize Majorana fermions. However, epitaxial growth of a superconductor on the TI surface to achieve a good proximity effect has been a challenge. We discovered that simply depositing Pd on thin films of the TI material (Bi\\(_{1-x}\\)Sb\\(_x\\))\\(_2\\)Te\\(_3\\) leads to an epitaxial self-formation of PdTe\\(_2\\) superconductor having the superconducting transition temperature of ~1 K. This self-formed superconductor proximitizes the TI, which is confirmed by the appearance of a supercurrent in Josephson-junction devices made on (Bi\\(_{1-x}\\)Sb\\(_x\\))\\(_2\\)Te\\(_3\\). This self-epitaxy phenomenon can be conveniently used for fabricating TI-based superconducting nanodevices to address the superconducting proximity effect in TIs.

The superconductor Sn\\(_{1-x}\\)In\\(_{x}\\)Te is derived from the topological crystalline insulator SnTe and is a candidate topological superconductor. So far, high-quality thin films of this material have not been available, even though such samples would be useful for addressing the nature of its superconductivity. Here we report the successful molecular beam epitaxy growth of superconducting Sn\\(_{1-x}\\)In\\(_{x}\\)Te films by using Bi\\(_2\\)Te\\(_3\\) as a buffer layer. The data obtained from tunnel junctions made on such films show the appearance of two superconducting gaps, which points to the coexistence of bulk and surface superconductivity. Given the spin-momentum locking of the surface states, the surface superconductivity is expected to be topological with an effective \\(p\\)-wave character. Since the topological surface states of SnTe consist of four Dirac cones, this platform offers an interesting playground for studying topological surface superconductivity with additional degrees of freedom.

When a topological insulator is made into a nanowire, the interplay between topology and size quantization gives rise to peculiar one-dimensional states whose energy dispersion can be manipulated by external fields. In the presence of proximity-induced superconductivity, these 1D states offer a tunable platform for Majorana zero modes. While the existence of such peculiar 1D states has been experimentally confirmed, the realization of robust proximity-induced superconductivity in topological-insulator nanowires remains a challenge. Here, we report the realization of superconducting topological-insulator nanowires based on (Bi\\(_{1-x}\\)Sb\\(_x\\))\\(_2\\)Te\\(_3\\) (BST) thin films. When two rectangular pads of palladium are deposited on a BST thin film with a separation of 100--200 nm, the BST beneath the pads is converted into a superconductor, leaving a nanowire of BST in-between. We found that the interface is epitaxial and has a high electronic transparency, leading to a robust superconductivity induced in the BST nanowire. Due to its suitable geometry for gate-tuning, this platform is promising for future studies of Majorana zero modes.

We have investigated the magnetoresistive behavior of Dirac semi-metal Cd3As2 down to low temperatures and in high magnetic fields. A positive and linear magnetoresistance (LMR) as large as 3100% is observed in a magnetic field of 14 T, on high-quality single crystals of Cd3As2 with ultra-low electron density and large Lande g factor. Such a large LMR occurs when the magnetic field is applied perpendicular to both the current and the (100) surface, and when the temperature is low such that the thermal energy is smaller than the Zeeman splitting energy. Tilting the magnetic field or raising the temperature all degrade the LMR, leading to a less pronounced quadratic behavior. We propose that the phenomenon of LMR is related to the peculiar field-induced shifting/distortion of the helical electrons' Fermi surfaces in momentum space.