The search for Majorana bound states (MBSs) has been fueled by the prospect of using their non-Abelian statistics for robust quantum computation. Two-dimensional superconducting topological materials ...have been predicted to host MBSs as zero-energy modes in vortex cores. By using scanning tunneling spectroscopy on the superconducting Dirac surface state of the iron-based superconductor FeTe
Se
, we observed a sharp zero-bias peak inside a vortex core that does not split when moving away from the vortex center. The evolution of the peak under varying magnetic field, temperature, and tunneling barrier is consistent with the tunneling to a nearly pure MBS, separated from nontopological bound states. This observation offers a potential platform for realizing and manipulating MBSs at a relatively high temperature.
Abstract
Iron-chalcogenide superconductors have emerged as a promising Majorana platform for topological quantum computation. By combining topological band and superconductivity in a single material, ...they provide significant advantage to realize isolated Majorana zero modes. However, iron-chalcogenide superconductors, especially Fe(Te,Se), suffer from strong inhomogeneity which may hamper their practical application. In addition, some iron-pnictide superconductors have been demonstrated to have topological surface states, yet no Majorana zero mode has been observed inside their vortices, raising a question of universality about this new Majorana platform. In this work, through angle-resolved photoemission spectroscopy and scanning tunneling microscopy/spectroscopy measurement, we identify Dirac surface states and Majorana zero modes, respectively, for the first time in an iron-pnictide superconductor, CaKFe
4
As
4
. More strikingly, the multiple vortex bound states with integer-quantization sequences can be accurately reproduced by our model calculation, firmly establishing Majorana nature of the zero mode.
Aims/Introduction
To compare the effects of gliclazide, liraglutide and metformin on body composition in patients with type 2 diabetes mellitus with non‐alcoholic fatty liver disease.
Materials and ...Methods
A total of 85 patients were randomly allocated to receive gliclazide (n = 27), liraglutide (n = 29) or metformin (n = 29) monotherapy for 24 weeks. Body composition was measured using dual‐energy X‐ray absorptiometry.
Results
Liraglutide and metformin reduced total, trunk, limb, android and gynoid fat mass; this also led to weight reduction. However, gliclazide treatment produced no significant changes in weight or fat mass, likely because reductions in fat mass were concomitant with increases in lean tissue mass. Blood glucose concentrations and glycated hemoglobin levels improved in all treatment arms; levels of the latter were lower in patients treated with liraglutide and metformin. Serum alanine aminotransferase concentrations decreased in all treatment arms, whereas serum aspartate aminotransferase concentrations were reduced only by liraglutide and metformin. In all patients, weight loss and total, trunk, limb, and android fat mass reductions were positively correlated with decreases in serum alanine aminotransferase and aspartate aminotransferase levels, whereas reductions in waist circumference were positively correlated with lower serum alanine aminotransferase levels.
Conclusions
Compared with gliclazide, liraglutide and metformin monotherapies result in greater weight loss, reductions in body fat mass, and better blood glucose control among type 2 diabetes mellitus patients with non‐alcoholic fatty liver disease. Reductions in weight, fat mass and waist circumference favorably affect hepatic function.
This single‐center, open‐label, prospective, randomized clinical trial examined the effect of liraglutide, metformin, and gliclazide on body composition in patients with type 2 diabetes and concomitant non‐alcoholic fatty liver disease. The results show that liraglutide and metformin are superior to gliclazide in terms of reducing body weight, body mass index, and body fat mass, and in terms of improving liver function and glycosylated hemoglobin levels. In addition, liraglutide and metformin were shown to reduce fat mass rather than lean tissue mass, which is helpful in improving the body weight and glycemic control. Weight remained stable in the gliclazide group; this resulted from identical reductions in fat mass and increases in lean tissue mass.
Abstract
The iron-based superconductor is emerging as a promising platform for Majorana zero mode, which can be used to implement topological quantum computation. One of the most significant advances ...of this platform is the appearance of large vortex level spacing that strongly protects Majorana zero mode from other low-lying quasiparticles. Despite the advantages in the context of physics research, the inhomogeneity of various aspects hampers the practical construction of topological qubits in the compounds studied so far. Here we show that the stoichiometric superconductor LiFeAs is a good candidate to overcome this obstacle. By using scanning tunneling microscopy, we discover that the Majorana zero modes, which are absent on the natural clean surface, can appear in vortices influenced by native impurities. Our detailed analysis reveals a new mechanism for the emergence of those Majorana zero modes, i.e. native tuning of bulk Dirac fermions. The discovery of Majorana zero modes in this homogeneous material, with a promise of tunability, offers an ideal material platform for manipulating and braiding Majorana zero modes, pushing one step forward towards topological quantum computation.
The safe and effective delivery of drugs is a major obstacle in the treatment of ischemic stroke. Exosomes hold great promise as an endogenous drug delivery nanosystem for the treatment of cerebral ...ischemia given their unique properties, including low immunogenicity, innate stability, high delivery efficiency, and ability to cross the blood-brain barrier (BBB). However, exosome insufficient targeting capability limits their clinical applications. In this study, the c(RGDyK) peptide has been conjugated to the exosome surface by an easy, rapid, and bio-orthogonal chemistry. In the transient middle cerebral artery occlusion (MCAO) mice model, The engineered c(RGDyK)-conjugated exosomes (cRGD-Exo) target the lesion region of the ischemic brain after intravenous administration. Furthermore, curcumin has been loaded onto the cRGD-Exo, and administration of these exosomes has resulted in a strong suppression of the inflammatory response and cellular apoptosis in the lesion region. The results suggest a targeting delivery vehicle for ischemic brain based on exosomes and provide a strategy for the rapid and large-scale production of functionalized exosomes.
Majorana zero modes (MZMs) are spatially localized, zero-energy fractional quasiparticles with non-Abelian braiding statistics that hold promise for topological quantum computing. Owing to the ...particle-antiparticle equivalence, MZMs exhibit quantized conductance at low temperature. By using variable-tunnel-coupled scanning tunneling spectroscopy, we studied tunneling conductance of vortex bound states on FeTe
Se
superconductors. We report observations of conductance plateaus as a function of tunnel coupling for zero-energy vortex bound states with values close to or even reaching the 2
/
quantum conductance (where
is the electron charge and
is Planck's constant). By contrast, no plateaus were observed on either finite energy vortex bound states or in the continuum of electronic states outside the superconducting gap. This behavior of the zero-mode conductance supports the existence of MZMs in FeTe
Se
.
Monolayer antimonene is fabricated on PdTe2 by an epitaxial method. Monolayer antimonene is theoretically predicted to have a large bandgap for nanoelectronic devices. Air‐exposure experiments ...indicate amazing chemical stability, which is great for device fabrication. A method to fabricate high‐quality monolayer antimonene with several great properties for novel electronic and optoelectronic applications is provided.
A
bstract
We present a detailed phenomenological study of the next-to-next-to-leading order (NNLO) QCD corrections for
t
-channel single top (anti-)quark production and its semi-leptonic decay at the ...CERN Large Hadron Collider (LHC). We find the NNLO corrections for the total inclusive rates at the LHC with different center of mass energies are generally smaller than the NLO corrections, indicative of improved convergence. However, they can be large for differential distributions, reaching a level of 10% or more in certain regions of the transverse momentum distributions of the top (anti-)quark and the pseudo-rapidity distributions of the leading jet in the event. In all cases the perturbative hard-scale uncertainties are greatly reduced after the NNLO corrections are included. We also show a comparison of the normalized parton-level distributions to recent data from the 8 TeV measurement of the ATLAS collaboration. The NNLO corrections tend to shift the theoretical predictions closer to the measured transverse momentum distribution of the top (anti)-quark. Importantly, for the LHC at 13 TeV, we present NNLO cross sections in a fiducial volume with decays of the top quark included.
Monolayer SixCy constitutes an important family of 2D materials that is predicted to feature a honeycomb structure and appreciable bandgaps. However, due to its binary chemical nature and the lack of ...bulk polymorphs with a layered structure, the fabrication of such materials has so far been challenging. Here, the synthesis of atomic monolayer Si9C15 on Ru (0001) and Rh(111) substrates is reported. A combination of scanning tunneling microscopy (STM), X‐ray photoelectron spectroscopy (XPS), scanning transmission electron microscopy (STEM), and density functional theory (DFT) calculations is used to infer that the 2D lattice of Si9C15 is a buckled honeycomb structure. Monolayer Si9C15 shows semiconducting behavior with a bandgap of ≈1.9 eV. Remarkably, the Si9C15 lattice remains intact after exposure to ambient conditions, indicating good air stability. The present work expands the 2D‐materials library and provides a promising platform for future studies in nanoelectronics and nanophotonics.
2D Si9C15 monolayer is fabricated on Ru (0001) and Rh(111) substrates via the reaction between Si and graphene under high temperatures. The as‐grown Si9C15 layer is micrometer‐scale, high quality, and single crystalline with a bandgap of ≈1.9 eV. Combined measurements and density functional calculations confirm the buckled honeycomb structure. The novel 2D material also shows good air stability.
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