A sufficiently large supercurrent can close the energy gap in a superconductor and create gapless quasiparticles through the Doppler shift of quasiparticle energy caused by finite Cooper pair ...momentum. In this gapless superconducting state, zero-energy quasiparticles reside on a segment of the normal-state Fermi surface, whereas the remaining Fermi surface is still gapped. We use quasiparticle interference to image the field-controlled Fermi surface of bismuth telluride (Bi
Te
) thin films under proximity effect from the superconductor niobium diselenide (NbSe
). A small applied in-plane magnetic field induces a screening supercurrent, which leads to finite-momentum pairing on the topological surface states of Bi
Te
. We identify distinct interference patterns that indicate a gapless superconducting state with a segmented Fermi surface. Our results reveal the strong impact of finite Cooper pair momentum on the quasiparticle spectrum.
SnSe is a promising thermoelectric material with record-breaking figure of merit. However, to date a comprehensive understanding of the electronic structure and most critically, the self-hole-doping ...mechanism in SnSe is still absent. Here we report the highly anisotropic electronic structure of SnSe investigated by angle-resolved photoemission spectroscopy, in which a unique pudding-mould-shaped valence band with quasi-linear energy dispersion is revealed. We prove that p-type doping in SnSe is extrinsically controlled by local phase segregation of SnSe
microdomains via interfacial charge transferring. The multivalley nature of the pudding-mould band is manifested in quantum transport by crystallographic axis-dependent weak localisation and exotic non-saturating negative magnetoresistance. Strikingly, quantum oscillations also reveal 3D Fermi surface with unusual interlayer coupling strength in p-SnSe, in which individual monolayers are interwoven by peculiar point dislocation defects. Our results suggest that defect engineering may provide versatile routes in improving the thermoelectric performance of the SnSe family.
Chlamydia psittaci pneumonia is a zoonotic infectious disease caused by Chlamydia psittaci. Diagnostic tools, including culture, serologic test and PCR-based methods, are available but prone to false ...negative results.
This report included five cases of Chlamydia psittaci pneumonia. Symptoms and signs common to all 5 cases included fever, coughing, generalized muscle ache, and most notably, inflammatory infiltration of the lungs upon chest CT and X-ray. Metagenomic next-generation sequencing (mNGS) revealed the presence of Chlamydia psittaci in biopsy lung tissue in 3 cases and bronchoalveolar lavage fluid in the remaining 2 cases. Three patients responded to doxycycline plus moxifloxacin; two patients responded to moxifloxacin alone.
mNGS could be used to diagnose Chlamydia psittaci pneumonia.
The Rhododendron sanguineum complex is endemic to alpine mountains of northwest Yunnan and southeast Tibet of China. Varieties in this complex exhibit distinct flower colors even at the bud stage. ...However, the underlying molecular regulations for the flower color variation have not been well characterized. Here, we investigated this via measuring flower reflectance profiles and comparative transcriptome analyses on three coexisting varieties of the R. sanguineum complex, with yellow flush pink, bright crimson, and deep blackish crimson flowers respectively. We compared the expression levels of differentially-expressed-genes (DEGs) of the anthocyanin / flavonoid biosynthesis pathway using RNA-seq and qRT-PCR data. We performed clustering analysis based on transcriptome-derived Single Nucleotide Polymorphisms (SNPs) data, and finally analyzed the promoter architecture of DEGs.
Reflectance spectra of the three color morphs varied distinctively in the range between 400 and 700 nm, with distinct differences in saturation, brightness, hue, and saturation/hue ratio, an indirect measurement of anthocyanin content. We identified 15,164 orthogroups that were shared among the three varieties. The SNP clustering analysis indicated that the varieties were not monophyletic. A total of 40 paralogous genes encoding 12 enzymes contributed to the flower color polymorphism. These anthocyanin biosynthesis-related genes were associated with synthesis, modification and transportation properties (RsCHS, RsCHI, RsF3H, RsF3'H, RsFLS, RsANS, RsAT, RsOMT, RsGST), as well as genes involved in catabolism and degradation (RsBGLU, RsPER, RsCAD). Variations in sequence and cis-acting elements of these genes might correlate with the anthocyanin accumulation, thus may contribute to the divergence of flower color in the R. sanguineum complex.
Our results suggested that the varieties are very closely related and flower color variations in the R. sanguineum complex correlate tightly with the differential expression levels of genes involved in the anabolic and catabolic synthesis network of anthocyanin. Our study provides a scenario involving intricate relationships between genetic mechanisms for floral coloration accompanied by gene flow among the varieties that may represent an early case of pollinator-mediated incipient sympatric speciation.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The long‐range magnetic ordering in frustrated magnetic systems is stabilized by coupling magnetic moments to various degrees of freedom, for example, by enhancing magnetic anisotropy via lattice ...distortion. Here, the unconventional spin‐lattice coupled metamagnetic properties of atomically‐thin CrOCl, a van der Waals antiferromagnet with inherent magnetic frustration rooted in the staggered square lattice, are reported. Using temperature‐ and angle‐dependent tunneling magnetoconductance (TMC), in complementary with magnetic torque and first‐principles calculations, the antiferromagnetic (AFM)‐to‐ferrimagnetic (FiM) metamagnetic transitions (MTs) of few‐layer CrOCl are revealed to be triggered by collective magnetic moment flipping rather than the established spin‐flop mechanism, when external magnetic field (H) enforces a lattice reconstruction interlocked with the five‐fold periodicity of the FiM phase. The spin‐lattice coupled MTs are manifested by drastic jumps in TMC, which show anomalous upshifts at the transition thresholds and persist much higher above the AFM Néel temperature. While the MTs exhibit distinctive triaxial anisotropy, reflecting divergent magnetocrystalline anisotropy of the c‐axis AFM ground state, the resulting FiM phase has an a‐c easy plane in which the magnetization axis is freely rotated by H. At the 2D limit, such a field‐tunable FiM phase may provide unique opportunities to explore exotic emergent phenomena and novel spintronics devices.
Distinct from the established spin‐flop type metamagnetism, this work reports the unconventional spin‐lattice interlocked metamagnetism in few‐layer CrOCl down to the monolayer thickness. These unconventional metamagnetic transitions produce a unique field‐tunable ferrimagnetic phase with the magnetization axis freely rotated by magnetic field within an easy plane.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Noncentrosymmetric transition-metal monopnictides, including TaAs, TaP, NbAs, and NbP, are emergent topological Weyl semimetals (WSMs) hosting exotic relativistic Weyl fermions. In this Rapid ...Communication, we elucidate the physical origin of the unprecedented charge carrier mobility of NbP, which can reach 1x10 super(7) cm super(2) V super(-1) s super(-1) at 1.5 K. Angle- and temperature-dependent quantum oscillations, supported by density function theory calculations, reveal that NbP has the coexistence of p- and n-type WSM pockets in the k sub(z)=1.16pi/c plane (W1-WSM) and in the k sub(z)=0 plane near the high symmetry points Sigma (W2-WSM), respectively. Uniquely, each W2-WSM pocket forms a large dumbbell-shaped Fermi surface enclosing two neighboring Weyl nodes with the opposite chirality. The magnetotransport in NbP is dominated by these highly anisotropic W2-WSM pockets, in which Weyl fermions are well protected from defect backscattering by real spin conservation associated to the chiral nodes. However, with a minimal doping of ~1% Cr, the mobility of NbP is degraded by more than two orders of magnitude, due to the invalidity of helicity protection to magnetic impurities. Helicity protected Weyl fermion transport is also manifested in chiral anomaly induced negative magnetoresistance, controlled by the W1-WSM states. In the quantum regime below 10 K, the intervalley scattering time by impurities becomes a large constant, producing the sharp and nearly identical conductivity enhancement at low magnetic field.
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CMK, CTK, FMFMET, IJS, NUK, PNG, UM
2D materials with nontrivial energy bands are highly desirable for exploring various topological phases of matter, as low dimensionality opens unprecedented opportunities for manipulating the quantum ...states. Here, it is reported that monolayer (ML) dialkali‐metal monoxides, in the well‐known 2H‐MoS2 type lattice, host multiple symmetry‐protected topological phases with emergent fermions, which can be effectively tuned by strain engineering. Based on first‐principles calculations, it is found that in the equilibrium state, ML Na2O is a 2D double Weyl semimetal, while ML K2O is a 2D pseudospin‐1 metal. These exotic topological states exhibit a range of fascinating effects, including universal optical absorbance, super Klein tunneling, and super collimation effect. By introducing biaxial or uniaxial strain, a series of quantum phase transitions between 2D double Weyl semimetal, 2D Dirac semimetal, 2D pseudospin‐1 metal, and semiconductor phases can be realized. The results suggest monolayer dialkali‐metal monoxides as a promising platform to explore fascinating physical phenomena associated with novel 2D emergent fermions.
2H‐MoS2 type metal‐shrouded oxides named dialkali‐metal monoxides are predicted to host multiple topological phases with exotic quasiparticle excitations, including double Weyl, 2D Dirac, 2D pseudospin‐1 metal, and semiconductor phases. These phases can be effectively tuned and manipulated by strain engineering and can be manifested by various fascinating effects such as super Klein tunneling and super collimation effect.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
In this paper, a multipath convolutional neural network (MP-CNN) is proposed for rehabilitation exercise recognition using sensor data. It consists of two novel components: a dynamic convolutional ...neural network (D-CNN) and a state transition probability CNN (S-CNN). In the D-CNN, Gaussian mixture models (GMMs) are exploited to capture the distribution of sensor data for the body movements of the physical rehabilitation exercises. Then, the input signals and the GMMs are screened into different segments. These form multiple paths in the CNN. The S-CNN uses a modified Lempel⁻Ziv⁻Welch (LZW) algorithm to extract the transition probabilities of hidden states as discriminate features of different movements. Then, the D-CNN and the S-CNN are combined to build the MP-CNN. To evaluate the rehabilitation exercise, a special evaluation matrix is proposed along with the deep learning classifier to learn the general feature representation for each class of rehabilitation exercise at different levels. Then, for any rehabilitation exercise, it can be classified by the deep learning model and compared to the learned best features. The distance to the best feature is used as the score for the evaluation. We demonstrate our method with our collected dataset and several activity recognition datasets. The classification results are superior when compared to those obtained using other deep learning models, and the evaluation scores are effective for practical applications.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Exciting phenomena may emerge in non-centrosymmetric two-dimensional electronic systems when spin-orbit coupling (SOC)
interplays dynamically with Coulomb interactions
, band topology
and external ...modulating forces
. Here we report synergetic effects between SOC and the Stark effect in centrosymmetric few-layer black arsenic, which manifest as particle-hole asymmetric Rashba valley formation and exotic quantum Hall states that are reversibly controlled by electrostatic gating. The unusual findings are rooted in the puckering square lattice of black arsenic, in which heavy 4p orbitals form a Brillouin zone-centred Γ valley with p
symmetry, coexisting with doubly degenerate D valleys of p
origin near the time-reversal-invariant momenta of the X points. When a perpendicular electric field breaks the structure inversion symmetry, strong Rashba SOC is activated for the p
bands, which produces spin-valley-flavoured D
valleys paired by time-reversal symmetry, whereas Rashba splitting of the Γ valley is constrained by the p
symmetry. Intriguingly, the giant Stark effect shows the same p
-orbital selectiveness, collectively shifting the valence band maximum of the D
Rashba valleys to exceed the Γ Rashba top. Such an orchestrating effect allows us to realize gate-tunable Rashba valley manipulations for two-dimensional hole gases, hallmarked by unconventional even-to-odd transitions in quantum Hall states due to the formation of a flavour-dependent Landau level spectrum. For two-dimensional electron gases, the quantization of the Γ Rashba valley is characterized by peculiar density-dependent transitions in the band topology from trivial parabolic pockets to helical Dirac fermions.
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GEOZS, IJS, IMTLJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK, ZAGLJ
The coupling between electric ordering and magnetic ordering in two-dimensional (2D) materials is important for both fundamental research of 2D multiferroics and future development of magnetism-based ...information storage and operation. Here, we introduce a scheme for realizing a magnetic phase transition through the transition of electric ordering. We take CuMoP
2
S
6
monolayer as an example, which is a member of the large 2D transition-metal chalcogen-phosphates family. Based on first-principles calculations, we find that it is a multiferroic with unprecedented characters, namely, it exhibits two different phases: an antiferroelectric-antiferromagnetic phase and a ferroelectric-ferromagnetic phase, in which the electric and magnetic orderings are strongly coupled. Importantly, the electric polarization is out-of-plane, so the magnetism can be readily switched by using the gate electric field. Our finding reveals a series of 2D multiferroics with special magnetoelectric coupling, which hold great promise for experimental realization and practical applications.
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