Junction Length Research Articles

Light-modulated 8-Pmmn borophene-based pure crossed Andreev reflection

Abstract We investigate the off-resonant circularly polarized light-modulated crossed Andreev reflection in an 8-Pmmn borophene-based normal conductor/superconductor/normal conductor junction. When the signs of Fermi energies in two normal regions are opposite, the pure crossed Andreev reflection without the local Andreev reflection and the elastic cotunneling occurs. By using the Dirac-Bogoliubov-de Gennes equation and the Blonder-Tinkham-Klapwijk formula, the pure crossed Andreev reflection conductance and its oscillation as a function of the junction length and the Fermi energy in the superconducting regions are discussed. It is found that the value of pure crossed Andreev reflection conductance peak value and its corresponding value of light-induced gap increase with the increase of incident energy of electron. Furthermore, the valley splitting for the transmitted hole is found due to the presence of tilted velocity of borophene. Our findings are beneficial for designing the high efficiency 8-Pmmn borophene-based nonlocal transistor and nonlocal valley splitter without local and non-entangled processes.

Josephson effect of massive pseudospin-1 fermions in the ferromagnetic dice lattice

We theoretically study the Josephson effect of massive pseudospin-1 fermions in a superconductor/ferromagnet/superconductor (S/F/S) junction based on the dice lattice, including Sz- and +U-type mass terms with the magnitude m. For the Sz-type fermions, it is found that, in the absence of ferromagnetic exchange field h, the supercurrent is effectively inhibited by m or the junction length L. In the presence of h, 0−π state transition can be realized by modulating h, m, or L. The m-induced state transition occurs more frequently for a larger h or L. Particularly, the inhibition of supercurrent caused by m still remains for a large m. In the doping case, corresponding to a nonzero EF, the m-induced state transition may disappear for a large h or L. With EF increased, the inhibition caused by m diminishes for a small h whereas intensifies for a large h. In addition, the supercurrent features for the +U-type fermions distinct from those for the Sz-type fermions are demonstrated.

Direct Microwave Spectroscopy of Andreev Bound States in Planar Ge Josephson Junctions

We demonstrate microwave measurements of the Andreev-bound-state (ABS) spectrum in planar Josephson junctions (JJs) defined in Ge high-mobility two-dimensional hole gases contacted by superconducting platinum germanosilicide (PtSiGe). The JJs and readout circuitry are located on separate chips and inductively coupled via flip-chip bonding. For a device with 350-nm junction length, the spectroscopic signatures were consistent with the short-junction limit, with an induced superconducting gap Δ∗≈48μeV and transmission τ≈0.94. The interaction between the highest-transmission ABS and the resonator was well described by a Jaynes-Cummings model with a vacuum Rabi splitting of approximately 6 MHz. A device with a junction length of 1μm showed an ABS spectrum consistent with a long-junction model. Time-resolved monitoring of the readout resonator in the dispersive regime revealed gate-voltage tunable-junction parity fluctuations on the time scale of seconds. Our work indicates a viable path toward hybrid quantum devices based on planar Ge. Published by the American Physical Society 2024

Josephson effect in a Fibonacci quasicrystal

Quasiperiodicity has recently been proposed to enhance superconductivity and its proximity effect. Simultaneously, there has been significant experimental progress in the fabrication of quasiperiodic structures, including in reduced dimensions. Motivated by these developments, we use microscopic tight-binding theory to investigate the DC Josephson effect through a ballistic Fibonacci chain attached to two superconducting leads. The Fibonacci chain is one of the most-studied examples of quasicrystals, hosting a rich multifractal spectrum, containing topological gaps with different winding numbers. We study how the Andreev-bound states (ABS), current-phase relation, and the critical current depend on the quasiperiodic degrees of freedom, from short to long junctions. While the current-phase relation shows a traditional 2π sinusoidal or sawtooth profile, we find that the ABS develop quasiperiodic oscillations and that the Andreev reflection is qualitatively altered, leading to quasiperiodic oscillations in the critical current as a function of junction length. Surprisingly, despite earlier proposals of quasiperiodicity enhancing superconductivity compared to crystalline junctions, we do not, in general, find that it enhances the critical current. However, we find significant current enhancement for reduced interface transparency because of the modified Andreev reflection. Furthermore, by varying the chemical potential, e.g., by an applied gate voltage, we find a fractal oscillation between superconductor-normal metal-superconductor (SNS) and superconductor-insulator-superconductor (SIS) behavior. Finally, we show that the winding of the subgap states leads to an equivalent winding in the critical current, such that the winding numbers, and thus the topological invariant, can be determined. Published by the American Physical Society 2024

Lévy noise-induced effects in a long Josephson junction in the presence of two different spatial noise distributions

We analyze the impact of Lévy-distributed stochastic fluctuations on the average switching time and voltage drop across a current-biased long Josephson tunnel junction. We compare the system’s response for two spatial configurations of time-dependent noise, i.e., homogeneous and distributed along the junction length. The response of the Josephson junction is explored by varying the characteristic parameter of the Lévy source, i.e., the α stability index and the noise intensity. These findings offer an effective tool to characterize a Lévy component possibly embedded in an unknown noise signal.

Combining mutation and recombination statistics to infer clonal families in antibody repertoires.

B-cell repertoires are characterized by a diverse set of receptors of distinct specificities generated through two processes of somatic diversification: V(D)J recombination and somatic hypermutations. B-cell clonal families stem from the same V(D)J recombination event, but differ in their hypermutations. Clonal families identification is key to understanding B-cell repertoire function, evolution, and dynamics. We present HILARy (high-precision inference of lineages in antibody repertoires), an efficient, fast, and precise method to identify clonal families from single- or paired-chain repertoire sequencing datasets. HILARy combines probabilistic models that capture the receptor generation and selection statistics with adapted clustering methods to achieve consistently high inference accuracy. It automatically leverages the phylogenetic signal of shared mutations in difficult repertoire subsets. Exploiting the high sensitivity of the method, we find the statistics of evolutionary properties such as the site frequency spectrum and dN/dS ratio do not depend on the junction length. We also identify a broad range of selection pressures spanning two orders of magnitude.

Quasiparticles-mediated thermal diode effect in Weyl Josephson junctions

We theoretically show quasiparticles-driven thermal diode effect (TDE) in an inversion symmetry-broken Weyl superconductor (WSC)-Weyl semimetal (WSM)-WSC Josephson junction. A Zeeman field perpendicular to the WSM region of the thermally-biased Weyl Josephson junction (WJJ) induces an asymmetry between the forward and reverse thermal currents, which is responsible for the TDE. Most interestingly, we show that the sign and magnitude of the thermal diode rectification coefficient is highly tunable by the superconducting phase difference and external Zeeman field, and also strongly depends on the junction length. The tunability of the rectification, particularly, the sign changing behavior associated with higher rectification enhances the potential of our WJJ thermal diode to use as functional switching components in thermal devices.

Plakins are involved in the regulation of centrosome position in polarized epithelial cells.

The control of epithelial cell polarity is key to their function. Its dysregulation is a major cause of tissue transformation. In polarized epithelial cells,the centrosome is off-centred toward the apical pole. This asymmetry determines the main orientation of the microtubule network and intra-cellular traffic. However, the mechanism regulating centrosome positioning at the apical pole of polarized epithelial cells is still poorly undertood. In this study we used transcriptomic data from breast cancer cells to identify molecular changes associated with the different stages of tumour transformation. We correlated these changes with variations in centrosome position or with cell progression along the epithelial-to-mesenchymal transition (EMT), a process that involves centrosome repositioning. We found that low levels of epiplakin, desmoplakin and periplakin correlated with centrosome mispositioning in cells that had progressed through EMT or tissue transformation. We further tested the causal role of these plakins in the regulation of centrosome position by knocking down their expression in a non-tumorigenic breast epithelial cell line (MCF10A). The downregulation of periplakin reduced the length of intercellular junction, which was not affected by the downregulation of epiplakin or desmoplakin. However, down-regulating any of them disrupted centrosome polarisation towards the junction without affecting microtubule stability. Altogether, these results demonstrated that epiplakin, desmoplakin and periplakin are involved in the maintenance of the peripheral position of the centrosome close to inter-cellular junctions. They also revealed that these plakins are downregulated during EMT and breast cancer progression, which are both associated with centrosome mispositioning. These results revealed that the down-regulation of plakins and the consequential centrosome mispositioning are key signatures of disorganised cytoskeleton networks, inter-cellular junction weakening, shape deregulation and the loss of polarity in breast cancer cells. These metrics could further be used as a new readouts for early phases of tumoral development.

Analysis of P-N Junction Length of Drain and Source in MOSFET Transistor Through TCAD Simulation

This paper delves into the convergence of mathematical and computer science principles within the realm of electronics engineering, particularly focusing on device-level transistor restructuring. A pressing challenge confronting the semiconductor sector is the persistent escalation of leakage current alongside technological advancements. At the heart of any chip or semiconductor device lies the transistor, serving as its fundamental building block. Among the various forms of leakage current, subthreshold leakage stands out as a dominant component in transistors. Within this study, a systematic exploration of the numerical association governing the physical configuration of MOSFET and leakage amount specifically the subthreshold one is undertaken. One innovative algorithm is crafted to facilitate the automated tracking of transistor structures, laying the groundwork for subsequent analyses. The simulation framework is meticulously constructed by leveraging mathematical formulations derived from the algorithmic outputs. Remarkably, the results obtained from the simulation conducted through TCAD software exhibit a remarkable proximity to established mathematical models. Given the ubiquity of Complementary Metal Oxide Semiconductor (CMOS) technology in contemporary semiconductor fabrication, it serves as the cornerstone for the simulation endeavours herein.

Analysis Of P-N Junction Length of Drain and Source in MOSFET Transistor Through TCAD Simulation

This paper delves into the convergence of mathematical and computer science principles within the realm of electronics engineering, particularly focusing on device-level transistor restructuring. A pressing challenge confronting the semiconductor sector is the persistent escalation of leakage current alongside technological advancements. At the heart of any chip or semiconductor device lies the transistor, serving as its fundamental building block. Among the various forms of leakage current, subthreshold leakage stands out as a dominant component in transistors. Within this study, a systematic exploration of the numerical association governing the physical configuration of MOSFET and leakage amount specifically the subthreshold one is undertaken. One innovative algorithm is crafted to facilitate the automated tracking of transistor structures, laying the groundwork for subsequent analyses. The simulation framework is meticulously constructed by leveraging mathematical formulations derived from the algorithmic outputs. Remarkably, the results obtained from the simulation conducted through TCAD software exhibit a remarkable proximity to established mathematical models. Given the ubiquity of Complementary Metal Oxide Semiconductor (CMOS) technology in contemporary semiconductor fabrication, it serves as the cornerstone for the simulation endeavours herein.

A New Equation to Estimate Peripherally Inserted Central Catheter Length.

Background and Objectives: Peripherally inserted central catheter (PICC) placement plays an important role in clinical practice. This study aimed to provide an equation for the proper estimation of catheter length in cases of PICC placement without imaging guidance in relation to patient height, weight, sex, and age. Materials and Methods: For 1137 PICC placement cases in both arm veins of 954 patients at a single center, the elbow crease to the cavoatrial junction length (ECL) was calculated as follows: ECL = (PICC length) + (distance from the elbow crease to the puncture site). We analyzed the relationship between ECL and patient characteristics and suggested a new equation for ECL based on height, weight, sex, and age. Results: The average ECL was 48.0 ± 2.4 cm in the right side and 51.0 ± 3.0 cm in the left side. ECL in the right arm was significantly correlated with patient height, sex, and age, whereas the ECL in the left arm was additionally significantly correlated with patient weight. The ECL (cm) prediction model was as follows: right ECL = 26.32 + 1.33 × (female = 1, male = 2) - 0.02 × age (years) + 0.13 × height (cm); left ECL = 22.09 + 1.28 × (female = 1, male = 2) + 0.02 × age (years) + 0.14 × height (cm) + 0.042 × weight (kg). Conclusions: The appropriate PICC length was predicted based on the patient's height, weight, sex, and age. The equations in our study can help predict the optimal catheter length and can be automatically calculated using computerized patient information for bedside procedures in PICC.

Intramolecular London Dispersion Interactions in Single-Molecule Junctions.

This work shows the first example of using intramolecular London dispersion interactions to control molecular geometry and quantum transport in single-molecule junctions. Flexible σ-bonded molecular junctions typically occupy straight-chain geometries due to steric effects. Here, we synthesize a series of thiomethyl-terminated oligo(dimethylsilmethylene)s that bear [CH2-Si(CH3)2]n repeat units, where all backbone dihedral states are sterically equivalent. Scanning tunneling microscopy break-junction (STM-BJ) measurements and theoretical calculations indicate that in the absence of a strong steric bias concerted intramolecular London dispersion interactions staple the carbosilane backbone into coiled conformations that remain intact even as the junction is stretched to its breakpoint. As these kinked conformations are highly resistive to electronic transport, we observe record-high conductance decay values on an experimental junction length basis (β = 1.86 ± 0.12 Å-1). These studies reveal the potential of using intramolecular London dispersion interactions to design single-molecule electronics.

Effects of Midcheek Lift According to Dissection Plane and Range: An Anatomical Study.

Midcheek lift has been performed for cosmetic or reconstructive surgery of the lower eyelid. For midcheek lift through the subciliary incision, preperiosteal and subperiosteal dissections are the most often implemented, with good clinical outcomes. However, a comparative assessment of the effects of these 2 methods had not been conducted. In this study we compared the effects of midcheek lift according to preperiosteal or subperiosteal plane and range of midfacial dissection. Forty hemifaces of 20 fresh cadavers were dissected. One side of the hemiface underwent preperiosteal dissection, and the other side underwent subperiosteal dissection. After dissections of 5, 10, 15, 20, and 30 mm and all of the midcheek area from the inferior orbital rim, the length of the elevated lid-cheek junction was measured by placing upward traction on the lateral portion of the lower lid. In both methods, the length of the midcheek lift increased as the dissection progressed, and the length of the lift on the lateral side was greater than that on the medial side. The length of the pulled skin in the preperiosteal group was the greatest in most cases. However, in the full dissection cases, the midcheek lift length was not statistically different between the 2 surgical methods, especially on the lateral side. Flap elevation in lower blepharoplasty surgery can be predicted based on the surgical method and dissection range. Implementing a surgical plan that takes this into account can enhance both reconstruction and aesthetic surgery outcomes in the midcheek area.

Poster 108: The Deep Region of the Supraspinatus Is Architecturally Distinct

Objectives: The supraspinatus (SSP) tendon is the most frequently involved in rotator cuff tears, a common orthopedic condition. Previous anatomical studies have described distinct anterior and posterior regions of the SSP muscle. The purpose of this study is to determine if the deep region of the supraspinatus muscle has significantly different architectural properties from the other regions. This could have implications on the mechanical and functional nature of the deep supraspinatus muscle. Methods: Architecture measurements were collected from 25 cadaver SSPs (Figure 1). There were 13 SSPs without a tear, 3 with partial tears, and 9 with full tears. The anterior to posterior dimension of the humeral head (APHH), musculotendinous junction length (MTJL), muscle mass and length were recorded. The muscle regions were demarcated as deep, [superficial] anterior, and [superficial] posterior. Raw and normalized fiber length, pennation angle, sarcomere length and number were analyzed for each region. Measurements were compared using repeated measures ANOVAs. The intact SSPs were analyzed first, and then a sub-analysis was performed based on presence of tear. Results: In 13 SSPs without tears (Figure 2), the deep region showed a lower mean pennation angle of 3.3±1.0° than the posterior region (11.0±3.9°, p<0.0001), which had a higher angle than the anterior region (7.6±2.6°, p=0.0005). Normalized fiber lengths in the deep region were 21.1% (p=0.0052) and 34.5% (p<0.0001) shorter than posterior and anterior, respectively. Deep region sarcomeres measured 3.4±0.2 µm compared to 3.1±0.2 µm (posterior, p=0.0012) and 3.2±0.2 µm (anterior, p=0.0390). Sarcomere number also decreased in the deep region by 21.2% (p=0.0056) and 34.2% (p<0.0001) compared to posterior and anterior regions, respectively. After including partial (n=3) and full (n=9) tears, all architecture measurements remained different in the deep region versus anterior or posterior. Finally, to help visualize the deep region of the SSP, diffusion tensor imaging with tractography was performed on a healthy volunteer’s MRI (Figure 3) to depict the tissue microstructure and muscle fiber orientation/length. Conclusions: The deep supraspinatus has lower pennation angles, shorter fiber lengths, and fewer but longer sarcomeres. These structural differences suggest a functionally unique ‘submuscle’ within the supraspinatus.

Conductance oscillations of antiferromagnetic layer tunnel junctions

We study conductance oscillations of antiferromagnetic layer tunnel junctions composed of antiferromagnetic topological insulators such as ${\mathrm{MnBi}}_{2}{\mathrm{Te}}_{4}$. In the presence of an in-plane magnetic field, we find that the two terminal differential conductances across the junction oscillates as a function of field strength. Notably, the quantum interference at weak fields for the even-layer case is distinctive from the odd-layer case due to the scattering phase shift $\ensuremath{\pi}$. Consequently, the differential conductance vanishes (maximized) at integer magnetic flux quanta for even-layer (odd-layer) junctions. The conductance oscillations manifest the layer-dependent quantum interference in which symmetries and scattering phases play essential roles. In numerical calculations, we observe that the quantum interference undergoes an evolution from superconducting quantum interference device-like to Fraunhofer-like oscillations as the junction length increases.

A hybrid deterministic-diffuse approach to the analysis of vibration transmission across finite junctions

The average vibro-acoustic performance of a junction between two-dimensional structural elements is often quantified by its diffuse vibration reduction index, especially for building structures. Existing prediction methods either assume an infinite junction length or consider non-diffuse transmission. In this work an approach for predicting the diffuse vibration reduction index of finite junctions of arbitrary complexity is developed. First, the mean and (co)variance of the diffuse coupling loss factor of a finite junction are obtained within the hybrid deterministic-statistical energy analysis framework. Dedicated basis functions are proposed to efficiently describe the interface displacements of the diffuse subsystems. Subsequently, the relation between the mean vibration reduction index and the coupling loss factor is established. It is demonstrated that this relation involves both the mean and the variance of the coupling loss factor. Additionally, the relation between the variance of the vibration reduction index and the (co)variances of the coupling loss factors is derived. Finally, the proposed approach is both numerically validated and compared to experimental results for several finite junctions between building elements, which are modelled as plates. For the numerical validation, the results obtained with the proposed approach are compared with those of an ensemble of junctions with the same bare structure but with point masses attached at random locations on the walls and floors. The validations demonstrate that an accurate prediction of the mean and variance of the diffuse vibration reduction index is possible when the uncertainty across the random ensemble is sufficiently large. The comparison to experimental results involves T and X junctions between directly coupled plates. At low and medium frequencies, the experimental data are well captured within the 95% confidence interval of the hybrid model results. At high frequencies, the uncertainty on the hybrid results is very small; such differences with the experimental data are caused by modelling errors.

Clinical outcomes and tendon lengthening after arthroscopic rotator cuff repair.

There is a phenomenon in which the tendon appears to increase the length after rotator cuff repair. However, it is unclear in which cases tendon lengthening occurs and how the degree of lengthening affects the surgical outcome. This study aimed to evaluate preoperative and postoperative musculotendinous junction (MTJ) and tendon length on magnetic resonance imaging and assess the postoperative tendon lengthening and its impact on postoperative outcomes. We reviewed 109 patients with good repair integrity after arthroscopic rotator cuff repair. Patients whose supraspinatus tendons were simply pulled out laterally without any additional procedures were included. They underwent serial magnetic resonance imaging before surgery and at 3, 6, and 24months after surgery. The location of the MTJ in relation to the line of the glenoid fossa and the supraspinatus tendon length were measured. Clinical evaluation was conducted 2years after surgery, including the range of shoulder motion, shoulder strength index (affected/unaffected strength), Constant score, University of California, Los Angeles score, and pain numeric rating scale. The characteristics of the preoperative tendon, change in tendon length over time, amount of the lateral shift of MTJ location and tendon length, and impact of tendon lengthening on postoperative clinical outcomes were analyzed. The preoperative tendon retraction significantly correlated with the MTJ location (r=-0.75; P<.0001) and preoperative tendon length (r=-0.46; P<.0001). The tendon length at 3, 6, and 24months after surgery was significantly longer than those before surgery (26.7±5.8mm, 27.9±6.6mm, 28.5±5.6mm, and 21.5±5.1mm, respectively). From before surgery to 24months after surgery, the MTJ location moved 8.4±8.6mm laterally and the tendon length increased 7.0±6.1mm. A significant and weak negative correlation was found between tendon lengthening and the abduction strength index (r=-0.22; P=.03); however, no significant correlation with pain, range of shoulder motion, external rotation strength index, Constant score, and University of California, Los Angeles score was found. Multiple linear regression analysis also showed that tendon lengthening was only associated with the abduction strength index (standardized coefficient=-0.20, P=.03). Tendon lengthening and lateral shift of MTJ location were observed after arthroscopic rotator cuff repair, and they correlated with preoperative tendon retraction. Although the amount of tendon lengthening had negative weak correlation with abduction strength index, it did not affect other postoperative outcomes.

Impact of Junction Length on Supercurrent Resilience against Magnetic Field in InSb-Al Nanowire Josephson Junctions.

Semiconducting nanowire Josephson junctions represent an attractive platform to investigate the anomalous Josephson effect and detect topological superconductivity. However, an external magnetic field generally suppresses the supercurrent through hybrid nanowire junctions and significantly limits the field range in which the supercurrent phenomena can be studied. In this work, we investigate the impact of the length of InSb-Al nanowire Josephson junctions on the supercurrent resilience against magnetic fields. We find that the critical parallel field of the supercurrent can be considerably enhanced by reducing the junction length. Particularly, in 30 nm long junctions supercurrent can persist up to 1.3 T parallel field─approaching the critical field of the superconducting film. Furthermore, we embed such short junctions into a superconducting loop and obtain the supercurrent interference at a parallel field of 1 T. Our findings are highly relevant for multiple experiments on hybrid nanowires requiring a magnetic-field-resilient supercurrent.

Revisiting Andreev processes in superconductor-graphene-superconductor (SGS) Josephson junctions: comparison with experimental results

In view of the recent progress in experiments on charge transport through various Josephson junctions made out of graphene, we have made a careful comparison between the theory and some of the available experimental results. Within the framework of a transfer matrix approach, we have first analytically derived the spectrum of Andreev bound states (ABS) in a superconductor -graphene-superconductor (SGS) junction for a wide range of experimentally relevant parameters. We have particularly considered the case of monolayer graphene (MLG). The theoretical results can account for both the retro Andreev reflection (RAR) and the specular Andreev reflection (SAR) in the relevant parameter range. Using the ABS spectrum we have evaluated the current through such junctions and the junction conductance from the analytically derived expressions at different bias voltages for a range of other system parameters directly taken from the experimental works. These theoretical results have then been compared with experimental results. Evaluated current and the conductance show scaling behaviour with change in the junction length and agree well with the experimental results. In the relevant parameter regime where the SAR process is dominant, the calculated values of the current and the conductivity have been found much lower than the corresponding values observed when the RAR process is dominant.

Non-local Andreev reflection through Andreev molecular states in graphene Josephson junctions

We propose that a device composed of two vertically stacked monolayer graphene Josephson junctions can be used for Cooper pair splitting. The hybridization of the Andreev bound states of the two Josephson junction can facilitate non-local transport in this normal-superconductor hybrid structure, which we study by calculating the non-local differential conductance. Assuming that one of the graphene layers is electron and the other is hole doped, we find that the non-local Andreev reflection can dominate the differential conductance of the system. Our setup does not require the precise control of junction length, doping, or super conducting phase difference, which could be an important advantage for experimental realization.