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Photonic spin Hall effect of monolayer black phosphorus in the Terahertz region
摘要： As a two-dimensional (2D) material, black phosphorus (BP) has attracted significant attention owing to exotic physical properties such as low-energy band gap, high carrier mobility, and strong in-plane anisotropy. The striking in-plane anisotropy is a promising candidate for novel light-matter interaction. Here, we investigate the photonic spin Hall effect (PSHE) on a monolayer of BP. Due to the in-plane anisotropic property of BP, the PSHE is accompanied with Goos-H?nchen and Imbert-Fedorov effects, resulting in an asymmetric spin splitting. The asymmetric spin splitting can be flexibly tuned by the angle between the incident plane and the armchair crystalline direction of BP and by the carrier density via a bias voltage. The centroid displacements of two opposite spin components of the reflected beam along directions parallel and perpendicular to the incident plane can be considered as four independent channels for information processing. The potential application in barcode-encryption is proposed and discussed. These findings provide a deeper insight into the spin-orbit interaction in 2D material and thereby facilitate the development of optoelectronic devices in the Terahertz region.
关键词： in-plane anisotropy,two-dimensional material,black phosphorus,photonic spin Hall effect
更新于2025-09-10 09:29:36
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[IEEE 2018 IEEE International Symposium on the Physical and Failure Analysis of Integrated Circuits (IPFA) - Singapore (2018.7.16-2018.7.19)] 2018 IEEE International Symposium on the Physical and Failure Analysis of Integrated Circuits (IPFA) - Evaluation of the Thermal Properties for the Design of the Semiconductor Device
摘要： The more semiconductor devices progress, the more importance of caring about heat dissipation from heat generation increase. This is called “Thermal design”. Thermophysical property values like thermal conductivity and thermal expansion coefficient are used as information for thermal design. The specified values in a brochure or literature data of similar materials are usually used as the thermophysical property values for the thermal design. However, when those values are used for simulation, the results may be wrong because an actual measured value such as rate of conduction of heat of an ingredient is different from literature data or the nominal value in many cases. It is thought that there are a lot of cases without considering directionality of an ingredient (anisotropy) and influence of joint interface. We propose that we should measure these values with considering anisotropy, size effect and the bonding state and utilize them for thermal design of electronic materials used in a semiconductor device.
关键词： Thermal diffusivity,Thermal conductivity,Thin film,Thermal resistance,Bonding layer,Anisotropy,Thermal design,Transient thermal measurement
更新于2025-09-10 09:29:36
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SPECTRAL DOMAIN ANALYSIS OF GYROTROPIC ANISOTROPY CHIRAL EFFECT ON THE INPUT IMPEDANCE OF A PRINTED DIPOLE ANTENNA
摘要： A theoretical analysis of a printed dipole antenna on a gyrotropic-anisotropy chiral dielectric substrate is presented. The study is based on numerical techniques for the characterization of electromagnetic propagation in chiral media. The general complex wave equation and the dispersion relation for such a medium are derived in the spectral domain. The spectral Green’s function of a grounded dielectric chiral slab is developed, and the spectral domain moment method impedance matrix elements are calculated. The e?ect of the chiral gyrotropy element on the input impedance of a dipole antenna printed on a grounded chiral substrate is analyzed using the Galerkin-based Method of Moments.
关键词： printed dipole antenna,Method of Moments,Green’s function,gyrotropic-anisotropy chiral dielectric substrate,spectral domain
更新于2025-09-10 09:29:36
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Influences of Asymmetrical Geometric Structures on the Birefringence of Index-Guiding Photonic Crystal Fiber
摘要： We have numerically investigated the influences of asymmetrical geometric structures on the birefringence of the index-guiding photonic crystal fiber (IG-PCF), by the finite element method. The structure of a reported highly birefringent (HB) PCF with artificial defect in the core is modified to destruct the symmetry. Our proposed structural modifications include elliptical air hole cladding, squeezing lattice of air holes, rotational elliptical air holes, and horizontally shifted air holes, in the cladding. It is found that the birefringence is sensitive to the modifications in different cases due to the different mechanisms. For 1550 nm wavelength, the optimized birefringence can be obtained to be 0.0328 by the elliptical air holes with the major semi-axis in the direction of the long side of the rectangular core region. Furthermore, for the HB-PCF by the asymmetric core shape, the structural factor restricting the further increase of birefringence is that continuous increase of asymmetry leading to the multi-core transmission. It seems to be that This work is not only a proposing of the optimal design of HB-PCF, but also a reference of founding the essence of geometric birefringence.
关键词： structural anisotropy,high birefringence,polarization-maintaining fiber,Photonic crystal fiber (PCF),geometric birefringence
更新于2025-09-10 09:29:36
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Optical and Magneto-Optical Properties of Multilayer Nanosized [Co/TiO2]n Films
摘要： The optical and magneto-optical properties of the metal–dielectric multilayer [Co/TiO2]n structures with 2–4-nm-thick layers prepared on a silicon substrate Si(001) by ion-beam deposition have been studied. The complex permittivity of multilayer [Co/TiO2]n structures has been measured by the optical ellipsometry technique in the spectral range of 0.6–5.6 eV and analyzed using the optical reflection matrices for isotropic multilayer dielectric structures taking into account the optical losses and also using the method of anisotropic effective medium. The magneto-optical Kerr effect has been measured by the polarimetric technique in the spectral range of 1.2–4.5 eV in the polar and longitudinal geometries. The magnetic anisotropy type is determined on the base of the field dependences of the magneto-optical Kerr effect. It is found that the nanosized [Co/TiO2]n structures can be considered as artificial optically uniaxial media with a strong magnetic and optical anisotropy at room temperature.
关键词： silicon substrate,Co/TiO2,magneto-optical properties,multilayer nanosized films,optical properties,complex permittivity,magneto-optical Kerr effect,magnetic anisotropy,optical ellipsometry,ion-beam deposition
更新于2025-09-10 09:29:36
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Aptamers Improving Fluorescence Anisotropy and Fluorescence Polarization Assays for Small Molecules
摘要： Nucleic acid affinity probes, such as aptamers, have been combined with fluorescence anisotropy (FA) / fluorescence polarization (FP) technology for the development of a diverse range of assays. Formation of a complex between a small fluorescent molecule and its binding partner usually increases the overall size of the fluorescent molecule and decreases its rate of rotation, resulting in increases in fluorescence anisotropy/polarization. Structure-switching of the fluorescently labeled aptamers arising from target binding can also affect molecular volume, local rotation of the fluorophore, and/or fluorescence lifetime, causing changes in anisotropy/polarization. Incorporation of the unique adsorptive properties of single-stranded nucleic acid aptamers on nanomaterials, hybridization of aptamers with complementary sequences, and the amplifiable ability of nucleic acid aptamers have broadened the applications of fluorescence anisotropy assays and enhanced their sensitivity. This review focuses on aptamer-based fluorescence anisotropy assays for the detection of small molecules, such as therapeutic drugs, environmental contaminants, natural toxins, and metabolites.
关键词： aptamer,adenosine triphosphate (ATP),nanomaterials,anisotropy,cocaine,nucleic acids,toxins,DNAzyme,polarization,aflatoxin B1,ochratoxin A (OTA),tyrosinamide
更新于2025-09-10 09:29:36
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Heat-Treatment Induced Magnetic Anisotropy of GaMnSb Films
摘要： Conditions and mechanisms of controlled variation of the magnetic anisotropy of GaMnSb films containing magnetic MnSb nanoinclusions by means of heat treatment have been determined. For this purpose, the temperature and magnetic-field dependences of the magnetic moments of samples before and after thermal annealing were measured using a SQUID magnetometer. It is established that the heat treatment of GaMnSb films leads to a significant increase in the values of characteristics determined by the magnetic anisotropy, including the growth of blocking temperature (from 95 to 390 K) and the magnetic anisotropy field (from 330 to 630 Oe). Results of transmission electron microscopy investigation indicate that a change in the magnetic anisotropy of GaMnSb films as a result of their thermal annealing can be related to a transition of the crystalline structure of magnetic MnSb nanoinclusions from hexagonal (space group P62/mmc) to cubic (space group F-43m).
关键词： magnetic anisotropy,GaMnSb films,SQUID magnetometer,transmission electron microscopy,MnSb nanoinclusions,heat treatment
更新于2025-09-10 09:29:36
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First-principles investigation of the interface magnetic anisotropy of Fe/SrTiO<sub>3</sub>
摘要： Interface effects in the magnetic nanostructures play a critical role in the magnetic properties. By using the first-principles density functional theory calculations, we investigate the electronic and magnetic properties of Fe/SrTiO3 interfaces, in which both the nonpolar surface SrTiO3(001) and the polar surface SrTiO3(110) are considered. A particular emphasis is placed on the magnetic anisotropy energy (MAE). Compare MAE of the Fe/SrTiO3 interfaces and the corresponding Fe monolayers, we find the Fe/SrTiO3(001) interface decreases MAE, while the Fe/SrTiO3(110) interface increases MAE. The interface orbital hybridization and orbital magnetic moments are detailly analyzed to understand the different interface magnetic anisotropy. Our investigation indicates that interface engineering can be an effective way to modulate the magnetic properties.
关键词： Fe/SrTiO3 interfaces,interface orbital hybridization,first-principles calculations,magnetic anisotropy energy
更新于2025-09-09 09:28:46
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Excitonic complexes in anisotropic atomically thin two-dimensional materials: Black phosphorus and
摘要： The effect of anisotropy in the energy spectrum on the binding energy and structural properties of excitons, trions, and biexcitons is investigated. To this end we employ the stochastic variational method with a correlated Gaussian basis. We present results for the binding energy of different excitonic complexes in black phosphorus (bP) and TiS3 and compare them with recent results in the literature when available, for which we find good agreement. The binding energies of excitonic complexes in bP are larger than those in TiS3. We calculate the different average interparticle distances in bP and TiS3 and show that excitonic complexes in bP are strongly anisotropic whereas in TiS3 they are almost isotropic, even though the constituent particles have an anisotropic energy spectrum. This is also confirmed by the correlation functions.
关键词： biexciton,TiS3,binding energy,black phosphorus,trion,anisotropy,stochastic variational method,exciton
更新于2025-09-09 09:28:46
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The Study on Magnetization Reversal of Stripe-Domain Structure in Ni Wires Fabricated on a LiNbO? Substrate
摘要： We investigated the magnetization reversal process of Ni wires fabricated on a single-crystal Y-cut 128° LiNbO3 substrate using magnetoresistance measurement, Kerr microscopy, and micromagnetic simulation. Our study reveals the stripe-domain structure, which is originated by the competition between the shape magnetic anisotropy and additional magnetic anisotropy induced by the heterojunction, allows us to provide a pinning necessary to control the domain-wall displacement.
关键词： magnetic anisotropy,Kerr microscopy,magnetization reversal,magnetoresistance (MR),micromagnetic simulation
更新于2025-09-09 09:28:46