Nonlinear coupling of flexural mode and extensional bulk mode in micromechanical resonators
The effect of coupling between the extensional bulk mode and the flexural mode of a cantilever beam resonator has been experimentally studied by exciting the two modes simultaneously. The modal frequency shift of linear extensional bulk mode shows a quadratic relationship with the square of flexural mode's amplitude displacement, and a frequency shift up to 1492 Hz is observed when the flexural mode is driven by a AC signalVac of 3 V and a DC bias of 30 V. The flexural mode shows a Duffing-like behavior with a softening nonlinearity and its frequency shift is influenced not only by its own nonlinear amplitude-frequ...
Source: Applied Physics Letters - November 30, 2016 Category: Physics Authors: Tianyi Zhang, Juan Ren, Xueyong Wei, Zhuangde Jiang and Ronghua Huan Source Type: research
A sub-1-volt analog metal oxide memristive-based synaptic device with large conductance change for energy-efficient spike-based computing systems
Nanoscale metal oxide memristors have potential in the development of brain-inspired computingsystems that are scalable and efficient. In suchsystems, memristors represent the native electronic analogues of the biologicalsynapses. In this work, we show cerium oxide based bilayer memristors that are forming-free, low-voltage ( ∼|0.8 V|), energy-efficient (full on/off switching at ∼8 pJ with 20 ns pulses, intermediate states switching at ∼fJ), and reliable. Furthermore, pulse measurements reveal the analog nature of the memristive device; that is, it can directly be programmed to intermediateresistance states. Leve...
Source: Applied Physics Letters - November 30, 2016 Category: Physics Authors: Cheng-Chih Hsieh, Anupam Roy, Yao-Feng Chang, Davood Shahrjerdi and Sanjay K. Banerjee Source Type: research
Molecular floating-gate organic nonvolatile memory with a fully solution processed core architecture
In this paper, we demonstrated a floating-gate organic thin film transistor based nonvolatile memory, in which the core architecture was processed by a sequential three-stepsolutionspin-coating method. The molecularsemiconductor 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS-Pen) distributing in the matrix of polymer poly(styrene) (PS), acting as the floating-gate and tunneling layer, respectively, was processed by one-stepspin-coating from their blendingsolution. The effect of the proportion of TIPS-Pen in the matrix of PS on the memory performances ofdevices was researched. As a result, a good nonvolatile memory was a...
Source: Applied Physics Letters - November 30, 2016 Category: Physics Authors: Chao Wu, Wei Wang and Junfeng Song Source Type: research
Towards high performance CoFe2O4 isotropic nanocrystalline powder for permanent magnet applications
We report on a comparative study of high performance isotropiccobaltferrite (CoFe2O4)powder processed by dry andsurfactant assisted (wet) ballmilling.Milling times as short as 1.5 min (dry) and 6 min (wet) have resulted in a 4-fold increase incoercivity, with a maximum achieved value above 318 kA/m (4 kOe). The use ofsurfactant is shown to be advantageous in the formation of a more homogeneous structure constituted by non-agglomerated and strained nanoparticles. A record (BH) max value of 18.6 kJ m −3 (2.34 MGOe) has been obtained for isotropicpowder after post-processing annealing. This magnetic perf...
Source: Applied Physics Letters - November 30, 2016 Category: Physics Authors: F. J. Pedrosa, J. Rial, K. M. Golasinski, M. N. Guzik, A. Quesada, J. F. Fern ández, S. Deledda, J. Camarero and A. Bollero Source Type: research
Gate tunneling current and quantum capacitance in metal-oxide-semiconductor devices with graphene gate electrodes
Metal-oxide-semiconductor(MOS)devices withgraphene as themetal gateelectrode,silicon dioxide with thicknesses ranging from 5 to 20 nm as the dielectric, andp-typesilicon as the semiconductor arefabricated and characterized. It is found thatFowler-Nordheim (F-N)tunneling dominates the gatetunneling current in thesedevices for oxide thicknesses of 10 nm and larger, whereas fordevices with 5 nm oxide, directtunneling starts to play a role in determining the total gate current. Furthermore, the temperature dependences of the F-Ntunneling current for the 10 nmdevices are characterized in the temperature range 77 –...
Source: Applied Physics Letters - November 30, 2016 Category: Physics Authors: Yanbin An, Aniruddh Shekhawat, Ashkan Behnam, Eric Pop and Ant Ural Source Type: research
Optically active semiconductor nanopores for parallel molecule detection
We propose a detection scheme forcharged molecules or particles based on optically excitedsemiconductornanopores. By means of numerical simulations, we show that the band gap of thesemiconductornanopore can be tuned allowing actuation by light. Molecules translocating through thesemiconductornanopore modulate thefluorescence from thenanopore enabling molecule detection. Our approach will enable us to perform a parallel readout of a translocating molecule without the need of chemical modification of the translocating molecules. (Source: Applied Physics Letters)
Source: Applied Physics Letters - November 30, 2016 Category: Physics Authors: Paul V. Gwozdz, Sujatha Ramachandran, August Dorn, Andr é Drews, Abhishek Bhat and Robert H. Blick Source Type: research
Out-of-plane polarization induced in magnetically-doped topological insulator Bi1.37V0.03Sb0.6Te2Se by circularly polarized synchrotron radiation above a Curie temperature
By means of angle- and spin-resolvedphotoemission, we demonstrate a possibility of the out-of-plane spinpolarization of topological surface states and corresponding lifting of the Kramers degeneracy at theDirac point induced in magnetically-doped topological insulator Bi1.37V0.03Sb0.6Te2Se by circularly polarized synchrotron radiation (SR) at roomtemperature. It has been shown that the induced out-of-planepolarization is created due to an “optically”-generated uncompensated spin accumulation with transferring the induced torque to the diluted V 3d ions. We have found theoretically a relation between the imbalance in de...
Source: Applied Physics Letters - November 30, 2016 Category: Physics Authors: A. M. Shikin, A. A. Rybkina, I. I. Klimovskikh, M. V. Filianina, K. A. Kokh, O. E. Tereshchenko, P. N. Skirdkov, K. A. Zvezdin and A. K. Zvezdin Source Type: research
Low-current, narrow-linewidth microwave signal generation in NiMnSb based single-layer nanocontact spin-torque oscillators
We report on thefabrication ofnano-contact spin-torque oscillators based on single layers of the epitaxiallygrown half-metal NiMnSb with ultralowspin wave damping. We demonstrate magnetization auto-oscillations atmicrowave frequencies in the 1 –3 GHz range in out-of-plane magnetic fields. Threshold current densities as low as 3 × 1011 A m−2 are observed as well as minimum oscillationlinewidths of 200 kHz, both of which are much lower than the values achieved in conventional metallic spin-valve-based devices of comparable dimensions. These results enable thefabrication of spin transfer torque driven magnonic dev...
Source: Applied Physics Letters - November 30, 2016 Category: Physics Authors: P. D ürrenfeld, F. Gerhard, S. M. Mohseni, M. Ranjbar, S. R. Sani, S. Chung, C. Gould, L. W. Molenkamp and J. Åkerman Source Type: research
Prospect for tunneling anisotropic magneto-resistance in ferrimagnets: Spin-orbit coupling effects in Mn3Ge and Mn3Ga
Magneticanisotropic phenomena in Mn3Ge and Mn3Gaferrimagnets are studied by first-principles density functional theory calculations. We find a large positivemagnetic anisotropy energy, associated with the Mn-atoms in the 4d-crystallographic positions. Sizableanisotropy in the density of states is found in the vicinity of the Fermi energy, and suggests the promising possibility for the generation of a sizable tunnelinganisotropic magneto-resistance effect (TAMR). The use of theferrimagneticmaterials for TAMR magnetic tunnelingjunctions is discussed as a prospective alternative forferromagnetic and antiferromagnetic material...
Source: Applied Physics Letters - November 30, 2016 Category: Physics Authors: S. Khmelevskyi, A. B. Shick and P. Mohn Source Type: research
Stimulated emission via electron-hole plasma recombination in fully strained single InGaN/GaN heterostructures
The optical properties of fully coherently grown single InGaN/GaNheterostructures for12 (Source: Applied Physics Letters)
Source: Applied Physics Letters - November 30, 2016 Category: Physics Authors: A. Minj, M. F. Romero, Y. Wang, Ö. Tuna, M. Feneberg, R. Goldhahn, G. Schmerber, P. Ruterana, C. Giesen and M. Heuken Source Type: research
Diffusive dynamics on paper matrix
Writing with ink on a paper and the rapid diagnostics of diseases using paper cartridge, despite their remarkable diversities from application perspective, both involve the motion of a liquid from a source on a porous hydrophilic substrate. Here we bring out a generalization in the pertinentdynamics by appealing to the concerned ensemble-averaged transport with reference to the underlying molecular picture. Our results reveal that notwithstanding the associated complexities and diversities, the resultant liquid transportcharacteristics on a paper matrix, in a wide variety of applications, resemble universal diffusivedynami...
Source: Applied Physics Letters - November 29, 2016 Category: Physics Authors: Kaustav Chaudhury, Shantimoy Kar and Suman Chakraborty Source Type: research
Large piezoelectricity in electric-field modified single crystals of SrTiO3
Defect engineering is an effective and powerful tool to control the existing material properties and produce completely new ones, which are symmetry-forbidden in a defect-free crystal. For example, the application of astatic electric field to asingle crystal of SrTiO3 forms a strained near-surface layer through the migration of oxygenvacancies out of the area beneath the positively chargedelectrode. While it was previously shown that this near-surface phase holds pyroelectric properties, which are symmetry-forbidden in centrosymmetric bulk SrTiO3, this paper reports that the same phase is stronglypiezoelectric. We demonstr...
Source: Applied Physics Letters - November 29, 2016 Category: Physics Authors: B. Khanbabaee, E. Mehner, C. Richter, J. Hanzig, M. Zschornak, U. Pietsch, H. St öcker, T. Leisegang, D. C. Meyer and S. Gorfman Source Type: research
Morphology and crystalline-phase-dependent electrical insulating properties in tailored polypropylene for HVDC cables
Polypropylene (PP) has become one promisingmaterial to potentially replace the cross-link polyethylene used for highvoltage direct current cables. Besides the isotactic polypropylene, the block polypropylene (b-PP) and random polypropylene (r-PP) can be synthesized through the copolymerization of ethylene and propylene molecules. In this letter, the effect of morphology and crystalline phases on the insulatingelectrical properties of PP was investigated. It was found that the introduction of polyethylenemonomer resulted in the formation ofβ andγ phases inb-PP andr-PP. The results from thecharacteristic trap energy levels...
Source: Applied Physics Letters - November 29, 2016 Category: Physics Authors: Jun-Wei Zha, Hong-Da Yan, Wei-Kang Li and Zhi-Min Dang Source Type: research
Negative differential resistance in n-type noncompensated silicon at low temperature
We present the results on low temperature current-voltage characteristics of noncompensated Si doped by Sb. In the temperature range 1.9 –2.25 K and at electrical fields smaller than 1 V/cm, thenegative differential resistance(NDR) was observed. The externalmagnetic field enhances the region of theNDR. We attribute this effect to the delocalization of the D− states in the upper Hubbard band due to the accumulation of thecharge injected bycurrent. (Source: Applied Physics Letters)
Source: Applied Physics Letters - November 29, 2016 Category: Physics Authors: A. L. Danilyuk, A. G. Trafimenko, A. K. Fedotov, I. A. Svito and S. L. Prischepa Source Type: research
Atomic layer deposition of Nb-doped ZnO for thin film transistors
We present physical and electrical characterization of niobium-doped zinc oxide (NbZnO) forthin film transistor(TFT) applications. The NbZnO films weredeposited usingatomic layer deposition.X-ray diffraction measurements indicate that the crystallinity of the NbZnO films reduces with an increase in theNb content and lowerdeposition temperature. It was confirmed usingX-ray photoelectron spectroscopy thatNb5+ is present within the NbZnO matrix. Furthermore, photoluminescence indicates that the band gap of theZnO increases with a higherNb content, which is explained by the Burstein-Moss effect. ForTFT applications, a growth t...
Source: Applied Physics Letters - November 29, 2016 Category: Physics Authors: A. Shaw, J. S. Wrench, J. D. Jin, T. J. Whittles, I. Z. Mitrovic, M. Raja, V. R. Dhanak, P. R. Chalker and S. Hall Source Type: research
