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Photodetectors based on Weyl semimetal promise extreme performance in terms of highly sensitive, broadband and self-powered operation owing to its extraordinary material properties. Layered Type-II Weyl semimetal that break Lorentz invariance can be further integrated with other two-dimensional materials to form van der Waals heterostructures and realize multiple functionalities inheriting the advantages of other two-dimensional materials. Herein, we report the realization of a broadband self-powered photodetector based on Type-II Weyl semimetal T -MoTe . The prototype metal-MoTe -metal photodetector exhibits a responsivity of 0.40 mA W and specific directivity of 1.07 × 10 Jones with 43 μs response time at 532 nm. Broadband responses from 532 nm to 10.6 μm are experimentally tested with a potential detection range extendable to far-infrared and terahertz. Furthermore, we identify the response of the detector is polarization angle sensitive due to the anisotropic response of MoTe . The anisotropy is found to be wavelength dependent, and the degree of anisotropy increases as the excitation wavelength gets closer to the Weyl nodes. In addition, with power and temperature dependent photoresponse measurements, the photocurrent generation mechanisms are investigated. Our results suggest this emerging class of materials can be harnessed for broadband angle sensitive, self-powered photodetection with decent responsivities.

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Photosensing and energy harvesting based on exotic properties of quantum materials and new operation principles have great potential to break the fundamental performance limit of conventional photodetectors and solar cells. Weyl semimetals have demonstrated novel optoelectronic properties that promise potential applications in photodetection and energy harvesting arising from their gapless linear dispersion and Berry field enhanced nonlinear optical effect at the vicinity of Weyl nodes. In this work, we demonstrate robust photocurrent generation at the edge of Td-WTe2, a type-II Weyl semimetal, due to crystalline-symmetry breaking along certain crystal fracture directions and possibly enhanced by robust fermi-arc type surface states. This edge response is highly generic and arises universally in a wide class of quantum materials with similar crystal symmetries. The robust and generic edge current response provides a charge separation mechanism for photosensing and energy harvesting over broad wavelength range.

Arthroscopic reduction and fixation of a bony Bankart lesion can achieve good results in selected cases. The size of the reconstructed glenoid is crucial to the success of the surgery.

Reading is an important high-level cognitive function of the human brain, requiring interaction among multiple brain regions. Revealing differences between children's large-scale functional brain networks for reading tasks and those of adults helps us to understand how the functional network changes over reading development. Here we used functional magnetic resonance imaging data of 17 adults (19-28 years old) and 16 children (11-13 years old), and graph theoretical analyses to investigate age-related changes in large-scale functional networks during rhyming and meaning judgment tasks on pairs of visually presented Chinese characters. We found that: (1) adults had stronger inter-regional connectivity and nodal degree in occipital regions, while children had stronger inter-regional connectivity in temporal regions, suggesting that adults rely more on visual orthographic processing whereas children rely more on auditory phonological processing during reading. (2) Only adults showed between-task differences in inter-regional connectivity and nodal degree, whereas children showed no task differences, suggesting the topological organization of adults' reading network is more specialized. (3) Children showed greater inter-regional connectivity and nodal degree than adults in multiple subcortical regions; the hubs in children were more distributed in subcortical regions while the hubs in adults were more distributed in cortical regions. These findings suggest that reading development is manifested by a shift from reliance on subcortical to cortical regions. Taken together, our study suggests that Chinese reading development is supported by developmental changes in brain connectivity properties, and some of these changes may be domain-general while others may be specific to the reading domain.

As a class of stimuli-responsive materials, shape memory polymers (SMPs) have received great attention due to their scientific interest and promising applications in advanced technologies in different areas. [1,2] Dual-SMPs can memorize a programmed temporary shape defined by the applied force and fixed by switching the system from one state to the other. Various molecular relaxations and phase transitions, e.g., vitrification, crystallization, or less commonly used liquid crystal (LC) transition, can be employed to fix the temporary shape. It is also demonstrated that multi-SMPs can be fabricated based on multiple transitions or a broad transition. [3] When the reversible transition is triggered by external stimuli, [1,4] the SMP will recover to its permanent shape defined by a network embedded in the system. The network shall be robust enough to resist the plastic deformation when the temporary shape is programmed.The network can be made of chemical or physical crosslink points, leading to SMPs that are thermoset or thermoplastic. [1] While the former gives more stable shape memory performance, the latter is attractive due to the flexibility of processing. However, physical crosslinks based on noncovalent bond interactions, e.g., chain entanglement, hydrogen bond, and ionic interaction, are often less stable. [5] Chain sliding or reorganization occurred during deformation will result in poor shape memory properties. This is a fatal weakness for many thermoplastic SMPs, particularly when a large shape change is demanded, [6] such as in some biomedical devices [2a] and package materials. [6d] To obtain better SMPs combining thermoplastic and stable network, one elegant approach is to follow the strategy of vitrimer. [7a] One can make the network using dynamic covalent bonds, which can allow the SMP to be reshaped at high temperatures with the aid of a catalyst. [7] On the other hand, new thermoplastic SMPs with pure physical crosslink network are still desirable. For example, an excellent multi-SMP of a compositional gradient copolymer is recently reported, [3d] showing a microphase-separated structure similar to the thermoplastic elastomer of styrene-butadiene-styrene (SBS) triblock copolymer. Nevertheless, to make the thermoplastic SMPs with both ideal shape fixity (R f ) and shape recovery (R r ) for high strain (e.g., strain >400%) remains a great challenge. [5,6b] While the commonly applied physical crosslinks show their limitation, we attempt to find a new type of physical crosslink by utilizing a columnar LC structure. Here we report a novel thermoplastic high strain SMP of hemiphasmid sidechain polynorbornene (P1; Figure 1a). P1 exhibits a hexagonal columnar LC (Φ H ) phase and a broad Φ H -isotropic transition. It renders both the R f and R r approaching 100% for dual-shape memory effect (SME), even when a high strain of ≈600% is applied. It is also a multi-SMP. For triple and quadruple-SME, with the total strain higher than 400%, it can still give R f quite high and R r > 95% at each step....

Organic−inorganic hybrid nonlinear optical (NLO) crystals have been attracting increasing attention because of their unique ability to combine the structural diversity of the organic moiety and the high stability of the inorganic moiety. However, organic NLO genes are rare. Herein, a new organic NLO material gene, the 2aminopyrimidinium cation (C 4 H 6 N 3 ) + ((2AP) + ), is reported, which constructs a novel organic−inorganic hybrid (C 4 H 6 N 3 ) + (H 2 PO 3 ) − (2APP) that exhibits excellent NLO properties and thermal stability, e.g., strong second-harmonic generation (SHG) intensity (2 × KDP), large birefringence (0.225 at 589.3 nm), high laser-induced-damage threshold (1.7 × KDP), and one of the highest thermal stabilities among the metal-free-(2AP) + -containing compounds. Our first-principles theoretical studies confirm the dominant contribution of (2AP) + to optical properties. The inorganic phosphite anions well separate the (2AP) + cations to successfully eliminate the unwanted centrosymmetric trap that is induced by the dipole−dipole interactions between (2AP) + cations. Furthermore, the unique layered structure decorated by the uniformly oriented individual (2AP) + chromophores, dramatically enhances the quantum yield of purple fluorescence (Φ = 30.6%), which is 3 orders of magnitude higher than that of pure 2AP and its derivatives.