Publications by authors named "Chengyu Yan"

Centrosymmetric materials with site inversion asymmetries possess hidden spin polarization, which remains challenging to be converted into spin currents because the global inversion symmetry is still conserved. This study demonstrates the spin-polarized circular photocurrents in centrosymmetric transition metal dichalcogenide semiconductors at normal incidence without applying electric bias. The global inversion symmetry is broken by using a spatially-varying circularly polarized light beam, which could generate spin gradient owing to the hidden spin polarization.

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The open reduction of mandibular condyle neck fractures is difficult due to the limited surgical field and complex facial nerve structures. The most effective fixation method for narrow fractured segments is debated as standard double four-hole plate fixation is often not feasible. This research compared bone stability and force resistance between single-long-plate and double-short-plate fixations using clinical outcomes, a Sawbones mandible model, and finite element analysis.

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Immobilizing ligands is a crucial part of preparing optical sensors and directly connected to the sensitivity, stability, and other characteristics of sensors. In this work, an ordered porous layer interferometry (OPLI) system that can monitor the covalent coupling process of ligands in real time was developed. Films of silica colloidal crystal (SCC), as optical interference substrates, were surface modified by three different reagents: chloroacetic acid, glutaric anhydride, and carboxymethyl dextran.

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The hydrogels, because of their swelling properties in response to the environmental stimulus, are being widely considered for the design of controlled drug release systems. To meet the need for developing effective drug delivery methods, we developed special silica colloidal crystal (SCC)-embedded chitosan hydrogel films. The SCC films served as an interference substrate and drug storage layer, while the chitosan hydrogel served as a cover to regulate the drug release.

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van der Waals (vdW) Josephson junctions can possibly accelerate the development of an advanced superconducting device that utilizes the unique properties of two-dimensional (2D) transition metal dichalcogenide (TMD) superconductors such as spin-orbit coupling and spin-valley locking. Here, we fabricate vertically stacked NbS/NbS Josephson junctions using a modified all-dry transfer technique and characterize the device performance via systematic low-temperature transport measurements. The experimental results show that the superconducting transition temperature of the NbS/NbS Josephson junction is 5.

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Large-area high-quality graphene enabled by chemical vapor deposition (CVD) can possibly pave the path for advanced flexible electronics and spintronics. CVD-grown method utilizing liquid carbon precursor has recently been demonstrated as an appealing choice for mass graphene production, thanks to its low cost and safe operation. However, the quality of the graphene film has been the major obstacle for the implementation of the liquid-precursor-based CVD method.

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We report an all-electric integrable electron focusing lens in n-type GaAs. It is shown that a pronounced focusing peak takes place when the focal point aligns with an on-chip detector. The intensity and full width half maximum (FWHM) of the focusing peak are associated with the collimation of injected electrons.

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We report spin amplification using a capacitive beam splitter in n-type GaAs where the spin polarization is monitored via a transverse electron focusing measurement. It is shown that partially spin-polarized current injected by the emitter can be precisely controlled, and the spin polarization associated with it can be amplified by the beam splitter, such that a considerably high spin polarization of around 50% can be obtained. Additionally, the spin remains coherent as shown by the observation of quantum interference.

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We present experimental results of transverse electron-focusing measurements performed using n-type GaAs. In the presence of a small transverse magnetic field (B), electrons are focused from the injector to detector leading to focusing peaks periodic in B. We show that the odd-focusing peaks exhibit a split, where each sub-peak represents a population of a particular spin branch emanating from the injector.

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