Thickness-dependent electronic structure modulation of ferromagnetic films on shape memory alloy substrates based on a pure strain effect
Pure strain-inducedelectronic structure modulation inferromagneticfilms is critical for developing reliable strain-assistedspintronic devices with low power consumption. For the conventional electricity-controlled strain engineering, it is difficult to reveal the pure straineffect onelectronic structure tunability due to the inseparability of pure straineffect and surface chargeeffect. Here, a non-electrically controlled NiTishape memoryalloy was utilized as a strain output substrate to induce a pure strain on attached Fefilms through a thermally controlledshape memory effect. The pure strain inducedelectronic structure ev...
Source: Applied Physics Letters - November 21, 2016 Category: Physics Authors: Chun Feng, Di Hu, Kui Gong, Xumin Jiang, Jianjuan Yin, Yi Cao, Xiao-Lei Tang, Feng Yang, Zhongfu Zhou, Guanghua Yu and D. Andrew Evans Source Type: research
Intrinsic electron mobility limits in β-Ga2O3
By systematically comparing experimental and theoretical transport properties, we identify the polar opticalphononscattering as the dominant mechanism limitingelectron mobility inβ–Ga2O3 to (Source: Applied Physics Letters)
Source: Applied Physics Letters - November 21, 2016 Category: Physics Authors: Nan Ma, Nicholas Tanen, Amit Verma, Zhi Guo, Tengfei Luo, Huili (Grace) Xing and Debdeep Jena Source Type: research
Broadband planar achromatic anomalous reflector based on dispersion engineering of spoof surface plasmon polariton
Planar reflectors are generally composed of non-uniform inclusions positioned on conducting sheet. Restricted by strongdispersion of the inclusions, the reflection of planar reflectors is usually chromatic. In this letter, we first obtain thedispersion relation for planar achromatic anomalous reflector (PAAR). Then, we propose to realize thedispersion relation based ondispersion engineering of spoofsurface plasmon polariton (SSPP). Metallic blades structure is proposed to achieve the lineardispersion response by tailoring the weakdispersion region of SSPP. 6 metallic blade structures are designed to compose the super cell ...
Source: Applied Physics Letters - November 21, 2016 Category: Physics Authors: Jie Yang, Jiafu Wang, Yongfeng Li, Zhuoluo Wang, Hongya Chen, Xinhua Wang and Shaobo Qu Source Type: research
Influence of polarization on contact angle saturation during electrowetting
Electrowetting is widely used to manipulateliquids on adielectricsurface by changing the wettability of the solid-liquid interface using an externally appliedelectric field. While the contact angle can be adequately predicted at low fields using Lippmann's model, there is a large disagreement with experimental behavior at high fields, where the contact angle saturates. Previous attempts to explain this saturationeffect (by considering a range of different mechanisms) have led to models that are applicable only to limited field ranges. Here, we use a model for the solid-liquid interfacialsurface energy (based on a dipole-di...
Source: Applied Physics Letters - November 21, 2016 Category: Physics Authors: Chen Jiang, Hanbin Ma, David G. Hasko and Arokia Nathan Source Type: research
Studies of electron diffusion in photo-excited Ni using time-resolved X-ray diffraction
In this study, we investigated the electrondiffusion in a 150 nm thicknickelfilmdeposited on an indium antimonide substrate. A strain wave that mimics the heatdeposition profile is generated in the metal and propagates into theInSb, where it influences the temporal profile ofX-raysdiffracted fromInSb. We found that the strain pulse significantly deviated from a simple exponential profile, and that the two-temperaturemodel was needed to reproduce themeasured heatdeposition profile. Experimental results were compared to simulations based on the two-temperaturemodel carried out using commercial finite-element software pack...
Source: Applied Physics Letters - November 18, 2016 Category: Physics Authors: A. I. H. Persson, A. Jarnac, Xiaocui Wang, H. Enquist, A. Jurgilaitis and J. Larsson Source Type: research
Suppression of photothermal convection of microparticles in two dimensional nanoplasmonic optical lattice
Photothermalconvection has been a major obstacle for stable particle trapping inplasmonicoptical tweezer at high optical power. Here, we demonstrate a strategy to suppress theplasmonicphotothermalconvection by using vanishingly smallthermal expansion coefficient of water at low temperature. A simple square nanoplasmonic array is illuminated with a loosely Gaussian beam to produce a two dimensionaloptical lattice for trapping of micro particles. We observe stable particle trapping due to near-field optical gradient forces at elevated optical power at low temperature. In contrast, for the same optical power at room temperatu...
Source: Applied Physics Letters - November 18, 2016 Category: Physics Authors: Yi-Chung Chen, Gilad Yossifon and Ya-Tang Yang Source Type: research
Time-resolved photoacoustic measurement for evaluation of viscoelastic properties of biological tissues
In this letter, we proposed a method forviscoelastic characterization of biologicaltissues based on time-resolved photoacousticmeasurement. The theoretical and experimental study was performed on the influence ofviscoelasticity effects on photoacoustic generation. Taking the time delay between the photoacoustic signal and the exciting laser, theviscoelasticity distribution of biologicaltissues can be mapped. To validate our method, gelatin phantoms with different densities weremeasured. We also applied this method in discrimination between fat andliver to confirm the usefulness of theviscoelastic evaluation. Furthermore, p...
Source: Applied Physics Letters - November 17, 2016 Category: Physics Authors: Yue Zhao, Conggui Chen, Hongwei Liu, Sihua Yang and Da Xing Source Type: research
Reversible magnetocaloric effect in materials with first order phase transitions in cyclic magnetic fields: Fe48Rh52 and Sm0.6Sr0.4MnO3
Themagnetocaloric effect (MCE) in an Fe48Rh52 alloy and Sm0.6Sr0.4MnO3 manganite was studied in cyclicmagnetic fields. The adiabatictemperature change in the Fe48Rh52 alloy for amagnetic field change ( ΔB) of 8 T and a frequency (f) of 0.13 Hz reaches the highest value of (ΔTad) of −20.2 K at 298 K. The magnitude of the MCE in Sm0.6Sr0.4MnO3 reaches ΔTad = 6.1 K at the samemagnetic field change at 143 K. Thetemperature regions, where a strong MCE is exhibited in an alternatingmagnetic field, are bounded in both compounds. In the case of the Fe48Rh52 alloy, thetemperature range for this phenomenon is...
Source: Applied Physics Letters - November 17, 2016 Category: Physics Authors: A. M. Aliev, A. B. Batdalov, L. N. Khanov, A. P. Kamantsev, V. V. Koledov, A. V. Mashirov, V. G. Shavrov, R. M. Grechishkin, A. R. Kaul' and V. Sampath Source Type: research
Enhanced magnetocrystalline anisotropy in an ultra-dense array of air-exposed crystalline cobalt nanowires
Themagnetic anisotropy of an ultradense array of crystallinecobaltnanowires is investigated by means of broadbandferromagnetic resonance and magnetictorque measurements. The array isgrown epitaxially in solution on a Pt(111) film and consists of single crystalline metallicwires with a diameter of 6.2 nm and a center-to-center interwire distance of 9.6 nm. The shapeanisotropy and the Co hexagonal compact structure with the c-axis along thewire axis combine with each other to impose a perpendicularmagnetic anisotropy despite the high density of 8 × 1012 wires/in.2. The intrinsic uniaxialmagnetocrystallineanisotrop...
Source: Applied Physics Letters - November 17, 2016 Category: Physics Authors: I. S. Camara, C. Achkar, N. Liakakos, A. Pierrot, V. Pierron-Bohnes, Y. Henry, K. Soulantica, M. Respaud, T. Blon and M. Bailleul Source Type: research
Silicon induced stability and mobility of indium zinc oxide based bilayer thin film transistors
Indiumzinc oxide (IZO),silicon containing IZO, and IZO/IZO:Si bilayerthin films have been prepared by dual radio frequency magnetronsputtering on glass and SiO2/Si substrates for studying their chemical compositions and electrical characteristics in order to ascertain reliability forthin film transistor(TFT) applications. An attempt is therefore made here to fabricate single IZO and IZO/IZO:Si bilayerTFTs to study the effect offilm thickness,silicon incorporation, and bilayer active channel on device performance and negative biasillumination stress (NBIS) stability.TFTs with increasing single active IZO layer thickness exh...
Source: Applied Physics Letters - November 17, 2016 Category: Physics Authors: Ram Narayan Chauhan, Nidhi Tiwari, Po-Tsun Liu, Han-Ping D. Shieh and Jitendra Kumar Source Type: research
Thermal metamaterial for convergent transfer of conductive heat with high efficiency
It is crucially important to focusconductive heat in an efficient way, which has received much attention in energy science (say, solar cells), but is still far from being satisfactory due to the diffusive (divergent) nature of the heat. By developing atheory with hybrid transformations (rotation and stretch-compression), here we providetheoretical and experimental evidences for a type of thermalmetamaterial called thermal converger. The converger is capable of convergentlyconducting heat in contrast to the known divergent behavior of heatdiffusion, thus yielding a large heating region with high temperatures close to the he...
Source: Applied Physics Letters - November 17, 2016 Category: Physics Authors: Xiangying Shen, Chaoran Jiang, Ying Li and Jiping Huang Source Type: research
Plasmonic terahertz modulator based on a grating-coupled two-dimensional electron system
Electrically driven broadbandmodulator with large modulation depth and high speed is in high demand to meet the technical advancing and applications interahertz fields recently. So far, the single-particle non-resonant absorption mechanism described by the Drude conductivity has been utilized in most of the related researches but is still not efficient enough. Here we proposed and demonstrated a terahertzmodulator based on the collective electron plasma excitations(plasmons) in a grating-coupled two-dimensionalelectron gas in GaN/AlGaNheterostructure. By switching between the resonant and non-resonant conditions of the 2Dp...
Source: Applied Physics Letters - November 17, 2016 Category: Physics Authors: Y. D. Huang, Y. Yu, H. Qin, J. D. Sun, Z. P. Zhang, X. X. Li, J. J. Huang and Y. Cai Source Type: research
Monolithic single mode interband cascade lasers with wide wavelength tunability
Monolithic two-section interband cascade lasers offering a wide wavelength tunability in the wavelength range around 3.7 μm are presented. Stable single mode emission in several wavelength channels was realized using the concept of binary superimposedgratings and two-segment Vernier-tuning. The wavelength selective elements in the two segments were based on specially designed lateral metalgrating structures defined by electron beam lithography. A dual-step dryetch process provided electrical separation between the segments. Individualcurrent control of the segments allowed wavelength channel selection as well as contin...
Source: Applied Physics Letters - November 17, 2016 Category: Physics Authors: M. von Edlinger, R. Weih, J. Scheuermann, L. N ähle, M. Fischer, J. Koeth, M. Kamp and S. Höfling Source Type: research
Split-loop resonator array for microwave energy harvesting
In this paper, we propose a three-dimensional split-loopresonator composed of a bended wire, a metallic ground slab, and a coaxial line loaded with a lumped matchingresistor to mimic the input impedance of a rectifier. An ensemble of suchresonators can function as an efficientenergy harvester. Theenergy capture mechanism is explained by an equivalent circuit model. A 20 × 20resonator array is fabricated toresonate around 2.45 GHz. The simulated and measured results indicate that the proposedresonator array has nearly unityenergy conversion efficiency at theresonant frequency and is quite promising as anenergy harv...
Source: Applied Physics Letters - November 16, 2016 Category: Physics Authors: Shen-Yun Wang, Peng Xu, Wen Geyi and Zhewang Ma Source Type: research
Experimental evidence of negative quantum capacitance in topological insulator for sub-60-mV/decade steep switching device
As a three-dimensional topologicalinsulator (TI), bismuth telluride (Bi2Te3) has two-dimensionalelectron gas on itssurface where negative quantumcapacitance (NQC) can exist at a specific biasing condition. In order to experimentally confirm NQC in a TI, a metal –insulator–semiconductor (MIS)capacitor (i.e., metal –Bi2Te3–SiO2–silicon) is fabricated. The capacitance–voltage measurement of theMIS capacitor at 300 K shows that as the depletioncapacitance insilicon decreases, the totalcapacitance of theMIS capacitor, which consists of twocapacitors connected in series (i.e.,insulatorcapacitor and depletioncapaci...
Source: Applied Physics Letters - November 16, 2016 Category: Physics Authors: H. Choi, H. Lee, J. Park, H.-Y. Yu, T. G. Kim and C. Shin Source Type: research
