Evidence for chiral superconductivity in Kagome superconductor CsV3Sb5

The interplay among frustrated lattice geometry, nontrivial band topology and correlations yields rich quantum states of matter in Kagome systems. A class of recent Kagome metals, AV3Sb5 (A= K, Rb, Cs), exhibit a cascade of symmetry-breaking transitions, involving 3Q chiral charge ordering, electronic nematicity, roton pair density wave and superconductivity. The interdependence among multiple competing orders suggests unconventional superconductivity, the nature of which is yet to be resolved. Here, we report the electronic evidence for chiral superconducting domains with boundary supercurrent, a smoking-gun of chiral superconductivity, in intrinsic CsV3Sb5 akes. Magnetic field-free superconducting diode effects are observed with its polarity modulated by thermal histories, unveiling a spontaneous time-reversal-symmetry breaking within dynamical order parameter domains in the superconducting phase. Strikingly, the critical current exhibits double-slit superconducting interference patterns, when subjected to external magnetic field. This is attributed to the periodic modulation of supercurrent owing along chiral domain boundaries constrained by fluxoid quantization. Our results provide the direct demonstration of a time-reversal symmetry breaking superconducting order in Kagome systems, opening a potential for exploring exotic physics, e.g. Majorana zero modes, in this intriguing topological Kagome system.Comment: 16 pages,13 figure

Disordered structure for long-range charge density wave order in annealed crystals of magnetic kagome FeGe

Recently, charge density wave (CDW) has been observed well below the order of antiferromagnetism (AFM) in kagome FeGe in which magnetism and CDW are intertwined to form an emergent quantum ground state. The mechanism of CDW precipitating from an A-type AFM of Fe kagome sublattice is intensively debated. The structural distortion originating from the CDW has yet to be accurately determined in FeGe. Here we resolved the structure model of the CDW in annealed FeGe crystals through single crystal x-ray diffraction via a synchrotron radiation source. The annealed crystals exhibit strong CDW transition signals exemplified by sharp magnetic susceptibility drop and specific heat jump, as well as intense superlattice reflections from 2 $\times$ 2 $\times$ 2 CDW order. Occupational disorder of Ge atoms resulting from short-range CDW correlations above $T_\mathrm{CDW}$ has also been identified from the structure refinements. The dimerization of Ge atoms along c axis has been demonstrated to be the dominant distortion for CDW. The Fe kagome and Ge honeycomb sublattices only undergo subtle distortions. Occupational disorder of Ge atoms is also proved to exist in the CDW phase due to the random selection of partial Ge sites to be dimerized to realize the structural distortion. Our work paves the way to understanding the unconventional nature of CDW in FeGe not only by solving the structural distortion below $T_\mathrm{CDW}$ and identifying fluctuations above it but also by rationalizing the synthesis of high-quality crystals for in-depth investigations in the future.Comment: 18 pages, 4 figures. Comments are welcom

Research on the Estimation Method of the Stiffness Degeneration Index of Reinforced Concrete Members

Based on variable amplitude displacement cycle tests of 24 reinforced concrete members with different reinforcement conditions, the stiffness degradation index was proposed to describe the damage. The relationship between the stiffness degradation index, the displacement history, and the cumulative energy dissipation was studied; on this basis, an estimation method for the stiffness degradation index was proposed. By comparing the experimental values and estimated values of the stiffness degradation index, the proposed method provides promising prediction reliability and accuracy. The stiffness degradation index has an effective relationship with the structural design parameters. Based on the stiffness degradation index, the reinforced concrete members can be divided into five performance levels: no damage (DK,k < 0), mild damage (0 < DK,k ≤ 0.3), moderate damage (0.3 < DK,k ≤ 0.7), severe damage (0.7 < DK,k ≤ 0.9), and destruction (0.9 < DK,k ≤ 1), which can provide a good reference for the seismic design of reinforced concrete members. The increase in the transverse reinforcement ratio can significantly reduce the stiffness damage, and the effect is more obvious under the conditions of small ductility. Under the same conditions, the smaller the ductility condition is, the smaller the stiffness damage of the reinforced concrete members will be. Therefore, the control of the ductility condition and the increase in the transverse reinforcement ratio are stable and effective methods for controlling the stiffness damage of reinforced concrete members

Clues to potential dipolar-Kondo and RKKY interactions in a polar metal

Abstract The coexistence of electric dipoles and itinerant electrons in a solid was postulated decades ago, before being experimentally established in several ‘polar metals’ during the last decade. Here, we report a concentration-driven polar-to-nonpolar phase transition in electron-doped BaTiO3. Comparing our case with other polar metals, we find a particular threshold concentration (n *) linked to the dipole density (n d). The universal ratio $$\frac{{n}_{{{{\rm{d}}}}}}{{n}^{* }}\approx 8.0(6)$$ n d n * ≈ 8.0 ( 6 ) suggests a common mechanism across different polar systems, possibly explained by a dipolar Ruderman-Kittel-Kasuya-Yosida theory. Moreover, in BaTiO3, we observe enhanced thermopower and upturn on resistivity at low temperatures near n *, resembling the Kondo effect. We argue that local electric dipoles act as two-level-systems, whose fluctuations couple with surrounding electron clouds, giving rise to a potential dipolar-counterpart of the Kondo effect. Our findings unveil a mostly uncharted territory for exploring emerging physics associated with electron-dipole correlations, encouraging further theoretical work on dipolar-RKKY and Kondo interactions

Thermoelectric Properties of <i>n</i>-Type Bi₄O₄SeX₂ (X = Cl, Br)

The multiple anion superlattice Bi4O4SeCl2 has been reported to exhibit extremely low thermal conductivity along the stacking c-axis, making it a promising material for thermoelectric applications. In this study, we investigate the thermoelectric properties of Bi4O4SeX2 (X = Cl, Br) polycrystalline ceramics with different electron concentrations by adjusting the stoichiometry. Despite optimizing the electric transport, the thermal conductivity remained ultra-low and approached the Ioffe–Regel limit at high temperatures. Notably, our findings demonstrate that non-stoichiometric tuning is a promising approach for enhancing the thermoelectric performance of Bi4O4SeX2 by refining its electric transport, resulting in a figure of merit of up to 0.16 at 770 K

Quantitative Proteomic Analysis of Formalin-fixed and Paraffin-embedded Nasopharyngeal Carcinoma Using iTRAQ Labeling, Two-dimensional Liquid Chromatography, and Tandem Mass Spectrometry

Formalin-fixed, paraffin-embedded (FFPE) tissue specimens represent a potentially valuable resource for protein biomarker investigations. In this study, proteins were extracted by a heat-induced antigen retrieval technique combined with a retrieval solution containing 2% SDS from FFPE tissues of normal nasopharyngeal epithelial tissues (NNET) and three histological types of nasopharyngeal carcinoma (NPC) with diverse differentiation degrees. Then two-dimensional liquid chromatography-tandem mass spectrometry coupled with isobaric tags for relative and absolute quantification (iTRAQ) labeling was employed to quantitatively identify the differentially expressed proteins among the types of NPC FFPE tissues. Our study resulted in the identification of 730 unique proteins, the distributions of subcellular localizations and molecular functions of which were similar to those of the proteomic database of human NPC and NNET that we had set up based on the frozen tissues. Additionally, the relative expression levels of cathepsin D, keratin8, SFN, and stathmin1 identified and quantified in this report were consistent with the immunohistochemistry results acquired in our previous study. In conclusion, we have developed an effective approach to identifying protein changes in FFPE NPC tissues utilizing iTRAQ technology in conjunction with an economical and easily accessible sample preparation method. (J Histochem Cytochem 58:517–527, 2010

Signature construction and molecular subtype identification based on liver-specific genes for prediction of prognosis, immune activity, and anti-cancer drug sensitivity in hepatocellular carcinoma

Abstract Background Liver specific genes (LSGs) are crucial for hepatocyte differentiation and maintaining normal liver function. A deep understanding of LSGs and their heterogeneity in hepatocellular carcinoma (HCC) is necessary to provide clues for HCC diagnosis, prognosis, and treatment. Methods The bulk and single-cell RNA-seq data of HCC were downloaded from TCGA, ICGC, and GEO databases. Through unsupervised cluster analysis, LSGs-based HCC subtypes were identified in TCGA-HCC samples. The prognostic effects of the subtypes were investigated with survival analyses. With GSVA and Wilcoxon test, the LSGs score, stemness score, aging score, immune score and stromal score of the samples were estimated and compared. The HCC subtype-specific genes were identified. The subtypes and their differences were validated in ICGC-HCC samples. LASSO regression analysis was used for key gene selection and risk model construction for HCC overall survival. The model performance was estimated and validated. The key genes were validated for their heterogeneities in HCC cell lines with quantitative real-time PCR and at single-cell level. Their dysregulations were investigated at protein level. Their correlations with HCC response to anti-cancer drugs were estimated in HCC cell lines. Results We identified three LSGs-based HCC subtypes with different prognosis, tumor stemness, and aging level. The C1 subtype with low LSGs score and high immune score presented a poor survival, while the C2 subtype with high LSGs score and immune score indicated an enduring survival. Although no significant survival difference between C2 and C3 HCCs was shown, the C2 HCCs presented higher immune score and stroma score. The HCC subtypes and their differences were confirmed in ICGC-HCC dataset. A five-gene prognostic signature for HCC survival was constructed. Its good performance was shown in both the training and validation datasets. The five genes presented significant heterogeneities in different HCC cell lines and hepatocyte subclusters. Their dysregulations were confirmed at protein level. Furthermore, their significant associations with HCC sensitivities to anti-cancer drugs were shown. Conclusions LSGs-based HCC subtype classification and the five-gene risk model might provide useful clues not only for HCC stratification and risk prediction, but also for the development of more personalized therapies for effective HCC treatment