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Wereport a surface-dominant Josephson effect in superconductor–topologicalinsulator–superconductor (S–TI–S) devices, wherea Bi1.5Sb0.5Te1.7Se1.3(BSTS) crystal flake was adopted as an intervening TI between Alsuperconducting electrodes. We observed a Fraunhofer-type criticalcurrent modulation in a perpendicular magnetic field in an Al–TI–Aljunction for both local and nonlocal current biasing. Fraunhofer-typemodulation of the differential resistance was also observed in a neighboringAu–TI–Au normal junction when it was nonlocally biasedby the Al–TI–Al junction. In all cases, the Fraunhofer-likesignal was highly robust to the magnetic field up to the criticalfield of the Al electrodes, corresponding to the edge-stepped nonuniformsupercurrent density arising from the top and rough side surfacesof the BSTS flake, which strongly suggests that the Josephson couplingin a TI is established through the surface conducting channels thatare topologically protected. [ABSTRACT FROM AUTHOR]

Although regular endoscopic screening may help in early detection of gastric cancer, interval cancer remains a problem in the screening program. This study evaluated the association between regular endoscopic screening and interval cancer detection in the Korean National Cancer Screening Program (KNCSP). We defined three groups (regularly, irregularly, and not screened) according to the screening interval, and the trends in the interval cancer rate (ICR) between the groups were tested using the Cochran–Armitage test. The influence of regular endoscopic screening on the risk of interval cancer was evaluated using multivariable logistic regression. Among the 11,642,410 participants who underwent endoscopy, the overall ICR was 0.36 per 1000 negative screenings. The ICR of the not screened group (0.41) was the highest among the three groups and the risk of interval cancer in this group was 1.68 times higher (p < 0.001) than that in the regularly screened group. Women in their 40s who had regular screening with no history of intestinal metaplasia and gastric polyps would have the lowest probability of having interval cancer (0.005%). Regular participation in endoscopic screening programs for reducing the risk of interval cancer may help to improve the quality of screening programs. [ABSTRACT FROM AUTHOR]

Abstract We report on the fabrication and transport characteristics of van der Waals (vdW)-contacted planar Josephson junctions. In a device, two pieces of cleaved 2H-NbSe 2 superconducting flakes and a monolayer graphene sheet serve as the superconducting electrodes and the normal-conducting spacer, respectively. A stack of NbSe 2 −graphene−hexagonal-boron-nitride (hBN) heterostructure with clean and flat interfaces was prepared by a dry transfer technique. The outermost hBN layer protected the NbSe 2 −graphene−NbSe 2 Josephson junction from chemical contamination during the fabrication processes. The Josephson coupling was confirmed by a periodic modulation of the junction critical current I c in a perpendicular magnetic field. The temperature dependence of I c showed long and diffusive Josephson coupling characteristics. The temperature dependence of the superconducting gap, obtained from the multiple Andreev reflection features, followed the Bardeen−Cooper−Schrieffer (BCS) prediction. [ABSTRACT FROM AUTHOR]

Background and Aims: The rapid urease test (RUT) is widely used to detect Helicobacter pylori infection; however, it is not preferred as a monitoring strategy after eradication owing to its low sensitivity. In this study, we evaluated the diagnostic performance of RUT using the sweeping method, which overcomes the limitations of conventional tissue sampling methods after eradication., Methods: Patients who received H pylori eradication treatment were enrolled. Each of the sweeping and conventional methods was performed on the same patients to compare diagnostic performance. Urea breath test (UBT), histology, and polymerase chain reaction were performed to determine true infection. Logistic regression analysis was conducted to investigate reasons for discrepancies between the results of the 2 methods., Results: In 216 patients, the eradication success rate was 68.1%, and the sensitivity and specificity of the sweeping method were 0.812 and 0.912, respectively, whereas those of the conventional method were 0.391 and 0.993, respectively (P < .05 for all). The area under the receiver operating characteristic curve for the sweeping method was higher than that for the conventional method (0.862 vs 0.692, P < .001). The mean time to H pylori detection for the sweeping method was 4.7 ± 4.4 minutes and 12.3 ± 16.1 minutes for the conventional method (P < .001). The risk for inconsistent results between the 2 methods was the highest for UBT values of 1.4‰ to 2.4‰ (odds ratio, 3.8; P = .016)., Conclusions: The RUT with the sweeping method could potentially replace the tissue sampling method as a test to confirm H pylori eradication and be an alternative option to UBT for patients requiring endoscopy., Competing Interests: Disclosure All authors disclosed no financial relationships. This work was partly supported by the Korean College of Helicobacter and Upper Gastrointestinal Research Foundation Grant (no. KCHUGR-202101002)., (Copyright © 2024 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights reserved.)

Background/aims: Early diagnosis of esophageal cancer (EC) remains challenging despite the increasing frequency of endoscopic screenings globally. The rapidly increasing number of endoscopic screenings performed over a certain period might influence diagnostic performance. This study evaluated the association between the number of endoscopic screenings and EC detection rates in a nationwide cohort., Methods: This retrospective population-based study used the Korean National Cancer Screening Program database, comprising 32,774,742 males and females aged ≥40 years between 2015 and 2019. Negative binomial regression model and least-squares mean evaluation were used to assess the association between month of the year and EC detection rates., Results: This study enrolled 28,032,590 participants who underwent upper endoscopy. The number of participants in the fourth quarter (October to December: 10,923,142 [39.0%]) was 2.1 times higher than that in the first quarter (January to March: 5,085,087 [18.1%]); this trend continued for all 5 years. Contrarily, detection rates for EC in the fourth quarter (0.08/1,000 person) were half that in the first quarter (0.15/1,000 person). The odds of detecting EC were lowest in November; in 2015 the odds were 0.57 (95% confidence interval, 0.41 to 0.79; p=0.001) times lower and in 2016, they were 0.51 (95% confidence interval, 0.37 to 0.68; p<0.001) times lower compared to January. The predicted detection rates showed a decreasing trend toward the end of the year (p>0.05 for all)., Conclusions: The workload of endoscopists increased excessively with the rising number of endoscopies toward the end of the year, which was reflected by the decreased EC detection rates during this period.

Genomic alterations in tumors play a pivotal role in determining their clinical trajectory and responsiveness to treatment. Targeted panel sequencing (TPS) has served as a key clinical tool over the past decade, but advancements in sequencing costs and bioinformatics have now made whole-genome sequencing (WGS) a feasible single-assay approach for almost all cancer genomes in clinical settings. This paper reports on the findings of a prospective, single-center study exploring the real-world clinical utility of WGS (tumor and matched normal tissues) and has two primary objectives: (1) assessing actionability for therapeutic options and (2) providing clarity for clinical questions. Of the 120 patients with various solid cancers who were enrolled, 95 (79%) successfully received genomic reports within a median of 11 working days from sampling to reporting. Analysis of these 95 WGS reports revealed that 72% (68/95) yielded clinically relevant insights, with 69% (55/79) pertaining to therapeutic actionability and 81% (13/16) pertaining to clinical clarity. These benefits include the selection of informed therapeutics and/or active clinical trials based on the identification of driver mutations, tumor mutational burden (TMB) and mutational signatures, pathogenic germline variants that warrant genetic counseling, and information helpful for inferring cancer origin. Our findings highlight the potential of WGS as a comprehensive tool in precision oncology and suggests that it should be integrated into routine clinical practice to provide a complete image of the genomic landscape to enable tailored cancer management., (© 2024. The Author(s).)

Current-induced spin-orbit torque (SOT) offers substantial promise for the development of low-power, nonvolatile magnetic memory. Recently, a single-phase material concurrently exhibiting magnetism and the spin Hall effect has emerged as a scientifically and technologically interesting platform for realizing efficient and compact SOT systems. Here, we demonstrate external-magnetic-field-free switching of perpendicular magnetization in a single-phase ferromagnetic and spin Hall oxide SrRuO 3 . We delicately altered the local lattices of the top and bottom surface layers of SrRuO 3 , while retaining a quasi-homogeneous, single-crystalline nature of the SrRuO 3 bulk. This leads to unbalanced spin Hall effects between the top and bottom layers, enabling net SOT performance within single-layer ferromagnetic SrRuO 3 . Notably, our SrRuO 3 exhibits the highest SOT efficiency and lowest power consumption among all known single-layer systems under field-free conditions. Our method of artificially manipulating the local atomic structures will pave the way for advances in spin-orbitronics and the exploration of new SOT materials.

All-Van der Waals (vdW)-material-based heterostructures with atomically sharp interfaces offer a versatile platform for high-performing spintronic functionalities at room temperature. One of the key components is vdW topological insulators (TIs), which can produce a strong spin-orbit-torque (SOT) through the spin-momentum locking of their topological surface state (TSS). However, the relatively low conductance of the TSS introduces a current leakage problem through the bulk states of the TI or the adjacent ferromagnetic metal layers, reducing the interfacial charge-to-spin conversion efficiency (q ICS ). Here, a vdW heterostructure is used consisting of atomically-thin layers of a bulk-insulating TI Sn-doped Bi 1.1 Sb 0.9 Te 2 S 1 and a room-temperature ferromagnet Fe 3 GaTe 2, to enhance the relative current ratio on the TSS up to ≈20%. The resulting q ICS reaches ≈1.65 nm -1 and the critical current density J c ≈0.9 × 10 6  Acm -2 at 300 K, surpassing the performance of TI-based and heavy-metal-based SOT devices. These findings demonstrate that an all-vdW heterostructure with thickness optimization offers a promising platform for efficient current-controlled magnetization switching at room temperature., (© 2024 The Authors. Advanced Science published by Wiley‐VCH GmbH.)

We demonstrate that the mode number of Andreev bound states in bilayer graphene Josephson junctions can be modulated by controlling the superconducting coherence length in situ. By exploiting the quadratic band dispersion of bilayer graphene, we control the Fermi velocity and thus the coherence length via the application of electrostatic gating. Tunneling spectroscopy of the Andreev bound states reveals a crossover from short to long Josephson junction regimes as we approach the charge neutral point of the bilayer graphene. Furthermore, analysis of different mode numbers of the Andreev energy spectrum allows us to estimate the phase-dependent Josephson current quantitatively. Our Letter provides a new way for studying multimode Andreev levels by tuning the Fermi velocity.

We aimed to evaluate the survival benefits of coadministering statins and multityrosine kinase inhibitors (TKIs) in patients with advanced hepatocellular carcinoma (HCC). Data from the Health Insurance Review and Assessment Service in Korea (2010-2020) were utilized. Statin use (≥28 cumulative defined daily doses) was analyzed, with 1534 statin users matched to 6136 non-users (1:4 ratio) using propensity scores. Primary and secondary outcomes were overall survival (OS) and progression-free survival (PFS). Statin use significantly improved OS (hazard ratio [HR] 0.77, 95% confidence interval [CI] 0.72-0.82, p < 0.001) and PFS (HR 0.78, 95% CI 0.74-0.84, p < 0.001). Continuous or post-TKI statin users had better OS, while discontinuation after TKI use led to poorer OS. Both lipophilic and hydrophilic statins improved OS and PFS, particularly with ≥730 cumulative defined daily doses. In conclusion, combining statins and TKIs in patients with advanced HCC yielded significant survival benefits, influenced by statin dosage and duration. Continuous statin administration post-TKI treatment is crucial for improving outcomes in patients with HCC.

Background: Patients with Barcelona clinic liver cancer (BCLC) stage B hepatocellular carcinoma (HCC) are considerably heterogeneous in terms of tumor burden, liver function, and performance status. To improve the poor survival outcomes of these patients, treatment approaches other than transarterial chemoembolization (TACE), which is recommended by HCC guidelines, have been adopted in real-world clinical practice. We hypothesize that this non-adherence to treatment guidelines, particularly with respect to the use of liver resection, improves survival in patients with stage B HCC., Aim: To assess guideline adherence in South Korean patients with stage B HCC and study its impact on survival., Methods: A retrospective analysis was conducted using data from 2008 to 2016 obtained from the Korea Central Cancer Registry. Patients with stage B HCC were categorized into three treatment groups, guideline-adherent, upward, and downward, based on HCC guidelines recommended by the Asian Pacific Association for the Study of the Liver (APASL), the European Association for the Study of the Liver (EASL), and the American Association for the Study of Liver Diseases (AASLD). The primary outcome was HCC-related deaths; tumor recurrence served as the secondary outcome. Survival among the groups was compared using the Kaplan-Meier method and the log-rank test. Predictors of survival outcomes were identified using multivariable Cox regression analysis., Results: In South Korea, over the study period from 2008 to 2016, a notable trend was observed in adherence to HCC guidelines. Adherence to the EASL guidelines started relatively high, ranging from 77% to 80% between 2008 and 2012, but it gradually declined to 58.8% to 71.6% from 2013 to 2016. Adherence to the AASLD guidelines began at 71.7% to 75.9% from 2008 to 2010, and then it fluctuated between 49.2% and 73.8% from 2011 to 2016. In contrast, adherence to the APASL guidelines remained consistently high, staying within the range of 90.14% to 94.5% throughout the entire study period. Upward treatment, for example with liver resection, liver transplantation, or radiofrequency ablation, significantly improved the survival of patients with BCLC stage B HCC compared to that of patients treated in adherence to the guidelines (for patients analyzed according to the 2000 EASL guidelines, the 5-year survival rates were 63.4% vs 27.2%, P < 0.001), although results varied depending on the guidelines. Progression-free survival rates were also significantly improved upon the use of upward treatments in certain groups. Patients receiving upward treatments were typically < 70 years old, had platelet counts > 10 5 /μL, and serum albumin levels ≥ 3.5 g/dL., Conclusion: Adherence to guidelines significantly influences survival in South Korean stage B HCC patients. Curative treatments outperform TACE, but liver resection should be selected with caution due to disease heterogeneity., Competing Interests: Conflict-of-interest statement: The authors declare no conflicts of interest., (©The Author(s) 2023. Published by Baishideng Publishing Group Inc. All rights reserved.)

Trigeminal neuralgia (TN) is a unilateral disorder characterized by electric shock-like pain, abrupt onset and termination, and limited to one or more branches of the trigeminal nerve. Various therapeutic modalities for TN have been introduced. We searched for literature indexed in PubMed, Medline, and the National Library of Medicine and reviewed all relevant articles on non-surgical treatments for TN. Published studies were reviewed with no restrictions on date; reviews, clinical trials, animal studies, retrospective studies, and cases were included. Carbamazepine and oxcarbazepine are the recommended first-line pharmacotherapies. Interventional treatments should be considered when pharmacotherapy is insufficient or withdrawn because of adverse effects.

The long-term effect of Helicobacter pylori eradication on metachronous gastric neoplasm prevention after endoscopic submucosal dissection (ESD) of gastric adenoma is unclear. This study included patients with confirmed H. pylori infection after ESD with curative resection for gastric adenoma. Patients were divided based on the success of H. pylori eradication treatment into two groups: eradication and non-eradication. Patients with any newly detected lesion within 1 year after ESD and recurrence at the ESD site were excluded from the analysis. Further, 1:1 propensity score matching was also performed to eliminate baseline differences between the two groups. H. pylori eradication treatment was administered to 673 patients after ESD (163 in the successful eradication group and 510 in the non-eradication group). During the median follow-up periods of 25 and 39 months in the eradication and non-eradication groups, metachronous gastric neoplasm was identified in 6 (3.7%) and 22 patients (4.3%), respectively. Adjusted Cox analysis revealed that H. pylori eradication was not associated with increased risk of metachronous gastric neoplasm after ESD. Kaplan-Meier analysis in the matched population yielded similar findings ( p = 0.546). H. pylori eradication treatment was not associated with metachronous gastric neoplasm after ESD with curative resection for gastric adenoma.

Background & Aims: The faecal immunochemical test (FIT), a non-invasive test for screening colorectal cancer (CRC), is being increasingly understood to reflect heightened inflammation. We aimed to investigate the association between abnormal FIT results and onset of inflammatory bowel disease (IBD), a disease characterized with chronic gut mucosal inflammation., Methods: Participants in the Korean National Cancer Screening Program for CRC between 2009-2013 were analysed and divided into positive and negative FIT result groups. The incidence rates of IBD after screening were calculated after excluding cases of haemorrhoids, CRC, and IBD at baseline. Cox proportional hazard analyses were used to identify independent risk factors for IBD occurrence during follow-up, and 1:2 propensity score matching was performed as a sensitivity analysis., Results: In total, 229,594 and 815,361 participants were assigned to the positive and negative FIT result groups, respectively. The age- and sex-adjusted incidence rates of IBD in participants with positive and negative test results were 1.72 and 0.50 per 10,000 person-years, respectively. Adjusted Cox analysis revealed that FIT positivity was associated with a significantly higher risk of IBD (hazard ratio 2.93, 95% confidence interval: 2.46, 3.47, P <.001), which was consistent for both disease subtypes of ulcerative colitis and Crohn's disease. The results of Kaplan-Meier analysis in the matched population yielded identical findings., Conclusions: Abnormal FIT results could be a preceding sign of incident IBD in the general population. Those with positive FIT results and suspected IBD symptoms could benefit from regular screening for early disease detection., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Lee, Lee, Park, Ahn and Noh.)

Engineering quantum states through light-matter interaction has created a paradigm in condensed-matter physics. A representative example is the Floquet-Bloch state, which is generated by time-periodically driving the Bloch wavefunctions in crystals. Previous attempts to realize such states in condensed-matter systems have been limited by the transient nature of the Floquet states produced by optical pulses 1-3 , which masks the universal properties of non-equilibrium physics. Here we report the generation of steady Floquet-Andreev states in graphene Josephson junctions by continuous microwave application and direct measurement of their spectra by superconducting tunnelling spectroscopy. We present quantitative analysis of the spectral characteristics of the Floquet-Andreev states while varying the phase difference of the superconductors, the temperature, the microwave frequency and the power. The oscillations of the Floquet-Andreev-state spectrum with phase difference agreed with our theoretical calculations. Moreover, we confirmed the steady nature of the Floquet-Andreev states by establishing a sum rule of tunnelling conductance 4 , and analysed the spectral density of Floquet states depending on Floquet interaction strength. This study provides a basis for understanding and engineering non-equilibrium quantum states in nanodevices., (© 2021. The Author(s), under exclusive licence to Springer Nature Limited.)

Stacking two-dimensional van der Waals (vdW) materials rotated with respect to each other show versatility for studying exotic quantum phenomena. In particular, anisotropic layered materials have great potential for such twistronics applications, providing high tunability. Here, we report anisotropic superconducting order parameters in twisted Bi 2 Sr 2 CaCu 2 O 8+ x (Bi-2212) vdW junctions with an atomically clean vdW interface, achieved using the microcleave-and-stack technique. The vdW junctions with twist angles of 0° and 90° showed the maximum Josephson coupling, comparable to that of intrinsic Josephson junctions. As the twist angle approaches 45°, Josephson coupling is suppressed, and eventually disappears at 45°. The observed twist angle dependence of the Josephson coupling can be explained quantitatively by theoretical calculation with the d -wave superconducting order parameter of Bi-2212 and finite tunneling incoherence of the junction. Our results revealed the anisotropic nature of Bi-2212 and provided a novel fabrication technique for vdW-based twistronics platforms compatible with air-sensitive vdW materials.

To date, there exists no established endoscopic surveillance interval strategy after endoscopic submucosal dissection (ESD) for gastric adenoma. In this study, we suggest a risk factor-based statistical model for optimal surveillance intervals for gastric adenoma after ESD with curative resection. A cox proportional hazard model was applied to identify risk factors for recurrence after ESD. Patients (n = 698) were categorized into groups based on the identified risk factors. The cumulative density of recurrence over time was computed using a cubic splined baseline hazard function, and the customized surveillance interval was modeled for each risk group. The overall cumulative incidence of recurrence was 7.3% (n = 51). Risk factors associated with recurrence were male (hazard ratio [HR], 2.60, P = 0.030), protruded scar (HR, 3.18, P < 0.001), and age ≥ 59 years (HR, 1.05, P < 0.001). The surveillance interval for each group was developed by using the recurrence limit for the generated risk groups. According to the developed schedule, high-risk patients would have a maximum of seven surveillance visits for 5 years, whereas low-risk patients would have biennial surveillance for cancer screening. We proposed a simple and promising strategy for determining a better endoscopic surveillance interval by parameterizing diverse and group-specific recurrence risk factors into a well-known survival model., (© 2021. The Author(s).)

Background: High-fidelity simulators are highly useful in assessing clinical competency; they enable reliable and valid evaluation. Recently, the importance of peer assessment has been highlighted in healthcare education, and studies using peer assessment in healthcare, such as medicine, nursing, dentistry, and pharmacy, have examined the value of peer assessment. This study aimed to analyze inter-rater reliability between peers and instructors and examine differences in scores between peers and instructors in the assessment of high-fidelity-simulation-based clinical performance by medical students., Methods: This study analyzed the results of two clinical performance assessments of 34 groups of fifth-year students at Ajou University School of Medicine in 2020. This study utilized a modified Queen's Simulation Assessment Tool to measure four categories: primary assessment, diagnostic actions, therapeutic actions, and communication. In order to estimate inter-rater reliability, this study calculated the intraclass correlation coefficient and used the Bland and Altman method to analyze agreement between raters. A t-test was conducted to analyze the differences in evaluation scores between colleagues and faculty members. Group differences in assessment scores between peers and instructors were analyzed using the independent t-test., Results: Overall inter-rater reliability of clinical performance assessments was high. In addition, there were no significant differences in overall assessment scores between peers and instructors in the areas of primary assessment, diagnostic actions, therapeutic actions, and communication., Conclusions: The results indicated that peer assessment can be used as a reliable assessment method compared to instructor assessment when evaluating clinical competency using high-fidelity simulators. Efforts should be made to enable medical students to actively participate in the evaluation process as fellow assessors in high-fidelity-simulation-based assessment of clinical performance in situations similar to real clinical settings., (© 2021. The Author(s).)

Although the rapid urease test (RUT) is a simple method for detecting Helicobacter pylori (H. pylori) infection, it requires sufficient biopsy samples and its sensitivity varies depending on the site and condition of H. pylori infection. We compared the diagnostic performance of a "sweeping method" for H. pylori detection with the conventional biopsy sampling method in atrophic gastric conditions which can reduce RUT accuracy. This prospective study included 279 patients who underwent upper endoscopy to determine the presence of H. pylori infection. Gastric mucosa of both the antrum and the corpus were swabbed, and we named this method the "sweeping method". Biopsy sampling for the conventional method, histologic evaluation, and polymerase chain reaction were performed at the same time. The sensitivity, specificity, and accuracy of the sweeping method were 0.941, 0.826, and 0.903, respectively, compared to 0.685, 0.859, and 0.742, respectively, for the conventional biopsy method. The area under the receiver operating curve for the sweeping method was 0.884 versus 0.772 for the conventional method (P < 0.001). The sweeping method had a faster detection time than the conventional method. Compared to conventional biopsy sampling, the sweeping method with the RUT provided higher sensitivity and accuracy for the detection of H. pylori, with a faster detection time.

Sensitive microwave detectors are essential in radioastronomy 1 , dark-matter axion searches 2 and superconducting quantum information science 3,4 . The conventional strategy to obtain higher-sensitivity bolometry is the nanofabrication of ever smaller devices to augment the thermal response 5-7 . However, it is difficult to obtain efficient photon coupling and to maintain the material properties in a device with a large surface-to-volume ratio owing to surface contamination. Here we present an ultimately thin bolometric sensor based on monolayer graphene. To utilize the minute electronic specific heat and thermal conductivity of graphene, we develop a superconductor-graphene-superconductor Josephson junction 8-13 bolometer embedded in a microwave resonator with a resonance frequency of 7.9 gigahertz and over 99 per cent coupling efficiency. The dependence of the Josephson switching current on the operating temperature, charge density, input power and frequency shows a noise-equivalent power of 7 × 10 -19 watts per square-root hertz, which corresponds to an energy resolution of a single 32-gigahertz photon 14 , reaching the fundamental limit imposed by intrinsic thermal fluctuations at 0.19 kelvin. Our results establish that two-dimensional materials could enable the development of bolometers with the highest sensitivity allowed by the laws of thermodynamics.

Td-WTe 2 (non-centrosymmetric and orthorhombic), a type-II Weyl semimetal, is expected to have higher-order topological phases with topologically protected, helical one-dimensional hinge states when its Weyl points are annihilated. However, the detection of these hinge states is difficult due to the semimetallic behaviour of the bulk. In this study, we have spatially resolved the hinge states by analysing the magnetic field interference of the supercurrent in Nb-WTe 2 -Nb proximity Josephson junctions. The Josephson current along the a axis of the WTe 2 crystal, but not along the b axis, showed a sharp enhancement at the edges of the junction, and the amount of enhanced Josephson current was comparable to the upper limits of a single one-dimensional helical channel. Our experimental observations suggest a higher-order topological phase in WTe 2 and its corresponding anisotropic topological hinge states, in agreement with theoretical calculations. Our work paves the way for the study of hinge states in topological transition-metal dichalcogenides and analogous phases.

We present a quantum switch based on analogous Dirac fermion optics (DFO), in which the angle dependence of Klein tunneling is explicitly utilized to build tunable collimators and reflectors for the quantum wave function of Dirac fermions. We employ a dual-source design with a single flat reflector, which minimizes diffusive edge scattering and suppresses the background incoherent transmission. Our gate-tunable collimator-reflector device design enables the quantitative measurement of the net DFO contribution in the switching device operation. We obtain a full set of transmission coefficients between multiple leads of the device, separating the classical contribution from the coherent transport contribution. The DFO behavior demonstrated in this work requires no explicit energy gap. We demonstrate its robustness against thermal fluctuations up to 230 K and large bias current density up to 10 2 A/m, over a wide range of carrier densities. The characterizable and tunable optical components (collimator-reflector) coupled with the conjugated source electrodes developed in this work provide essential building blocks toward more advanced DFO circuits such as quantum interferometers. The capability of building optical circuit analogies at a microscopic scale with highly tunable electron wavelength paves a path toward highly integrated and electrically tunable electron-optical components and circuits., Competing Interests: The authors declare no conflict of interest.

A layered two-dimensional superconducting material 2H-NbSe 2 is used to build a van der Waals heterostructure, where a proximity-coupled superconducting order can be induced in the interfacing materials. Vertically stacked NbSe 2 -graphene-NbSe 2 is fabricated using van der Waals interlayer coupling, producing defect-free contacts with a high interfacial transparency. The atomically thin graphene layer allows the formation of a highly coherent proximity Josephson coupling between the two NbSe 2 flakes. The temperature dependence of the junction critical current (I c ) reveals short and ballistic Josephson coupling characteristics that agree with theoretical prediction. The strong Josephson coupling is confirmed by a large junction critical current density of 1.6 × 10 4 A/cm 2 , multiple Andreev reflections in the subgap structure of the differential conductance, and a magnetic-field modulation of I c . This is the first demonstration of strongly proximity-coupled Josephson junctions with extremely clean interfaces in a dry-transfer-stacked van der Waals heterostructure.