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Nature Nanotechnology

Laure Mercier de Lépinay, Benjamin Pigeau, Benjamin Besga, Pascal Vincent, Philippe Poncharal, Olivier Arcizet
The miniaturization of force probes into nanomechanical oscillators enables ultrasensitive investigations of forces on dimensions smaller than their characteristic length scales. It also unravels the vectorial character of the force field and how its topology impacts the measurement. Here we present an ultrasensitive method for imaging two-dimensional vectorial force fields by optomechanically following the bidimensional Brownian motion of a singly clamped nanowire. This approach relies on angular and spectral tomography of its quasi-frequency-degenerated transverse mechanical polarizations: immersing the nanoresonator in a vectorial force field not only shifts its eigenfrequencies but also rotates the orientation of the eigenmodes, as a nanocompass...
October 17, 2016: Nature Nanotechnology
Nicola Rossi, Floris R Braakman, Davide Cadeddu, Denis Vasyukov, Gözde Tütüncüoglu, Anna Fontcuberta I Morral, Martino Poggio
Self-assembled nanowire (NW) crystals can be grown into nearly defect-free nanomechanical resonators with exceptional properties, including small motional mass, high resonant frequency and low dissipation. Furthermore, by virtue of slight asymmetries in geometry, a NW's flexural modes are split into doublets oscillating along orthogonal axes. These characteristics make bottom-up grown NWs extremely sensitive vectorial force sensors. Here, taking advantage of its adaptability as a scanning probe, we use a single NW to image a sample surface...
October 17, 2016: Nature Nanotechnology
Arne Laucht, Rachpon Kalra, Stephanie Simmons, Juan P Dehollain, Juha T Muhonen, Fahd A Mohiyaddin, Solomon Freer, Fay E Hudson, Kohei M Itoh, David N Jamieson, Jeffrey C McCallum, Andrew S Dzurak, A Morello
Coherent dressing of a quantum two-level system provides access to a new quantum system with improved properties-a different and easily tunable level splitting, faster control and longer coherence times. In our work we investigate the properties of the dressed, donor-bound electron spin in silicon, and assess its potential as a quantum bit in scalable architectures. The two dressed spin-polariton levels constitute a quantum bit that can be coherently driven with an oscillating magnetic field, an oscillating electric field, frequency modulation of the driving field or a simple detuning pulse...
October 17, 2016: Nature Nanotechnology
Baohu Dai, Jizhuang Wang, Ze Xiong, Xiaojun Zhan, Wei Dai, Chien-Cheng Li, Shien-Ping Feng, Jinyao Tang
Phototaxis is commonly observed in motile photosynthetic microorganisms. For example, green algae are capable of swimming towards a light source (positive phototaxis) to receive more energy for photosynthesis, or away from a light source (negative phototaxis) to avoid radiation damage or to hide from predators. Recently, with the aim of applying nanoscale machinery to biomedical applications, various inorganic nanomotors based on different propulsion mechanisms have been demonstrated. The only method to control the direction of motion of these self-propelled micro/nanomotors is to incorporate a ferromagnetic material into their structure and use an external magnetic field for steering...
October 17, 2016: Nature Nanotechnology
Ayusman Sen
No abstract text is available yet for this article.
October 17, 2016: Nature Nanotechnology
Nicholas A Kotov
No abstract text is available yet for this article.
October 10, 2016: Nature Nanotechnology
Wenyu Zhao, Zhiyuan Liu, Ping Wei, Qingjie Zhang, Wanting Zhu, Xianli Su, Xinfeng Tang, Jihui Yang, Yong Liu, Jing Shi, Yimin Chao, Siqi Lin, Yanzhong Pei
How to suppress the performance deterioration of thermoelectric materials in the intrinsic excitation region remains a key challenge. The magnetic transition of permanent magnet nanoparticles from ferromagnetism to paramagnetism provides an effective approach to finding the solution to this challenge. Here, we have designed and prepared magnetic nanocomposite thermoelectric materials consisting of BaFe12O19 nanoparticles and Ba0.3In0.3Co4Sb12 matrix. It was found that the electrical transport behaviours of the nanocomposites are controlled by the magnetic transition of BaFe12O19 nanoparticles from ferromagnetism to paramagnetism...
October 10, 2016: Nature Nanotechnology
Timothy Alexander Baart, Takafumi Fujita, Christian Reichl, Werner Wegscheider, Lieven Mark Koenraad Vandersypen
Coherent interactions at a distance provide a powerful tool for quantum simulation and computation. The most common approach to realize an effective long-distance coupling 'on-chip' is to use a quantum mediator, as has been demonstrated for superconducting qubits and trapped ions. For quantum dot arrays, which combine a high degree of tunability with extremely long coherence times, the experimental demonstration of the time evolution of coherent spin-spin coupling via an intermediary system remains an important outstanding goal...
October 10, 2016: Nature Nanotechnology
Michael K L Man, Athanasios Margiolakis, Skylar Deckoff-Jones, Takaaki Harada, E Laine Wong, M Bala Murali Krishna, Julien Madéo, Andrew Winchester, Sidong Lei, Robert Vajtai, Pulickel M Ajayan, Keshav M Dani
Technological progress since the late twentieth century has centred on semiconductor devices, such as transistors, diodes and solar cells. At the heart of these devices is the internal motion of electrons through semiconductor materials due to applied electric fields or by the excitation of photocarriers. Imaging the motion of these electrons would provide unprecedented insight into this important phenomenon, but requires high spatial and temporal resolution. Current studies of electron dynamics in semiconductors are generally limited by the spatial resolution of optical probes, or by the temporal resolution of electronic probes...
October 10, 2016: Nature Nanotechnology
Junling Guo, Blaise L Tardy, Andrew J Christofferson, Yunlu Dai, Joseph J Richardson, Wei Zhu, Ming Hu, Yi Ju, Jiwei Cui, Raymond R Dagastine, Irene Yarovsky, Frank Caruso
The organized assembly of particles into superstructures is typically governed by specific molecular interactions or external directing factors associated with the particle building blocks, both of which are particle-dependent. These superstructures are of interest to a variety of fields because of their distinct mechanical, electronic, magnetic and optical properties. Here, we establish a facile route to a diverse range of superstructures based on the polyphenol surface-functionalization of micro- and nanoparticles, nanowires, nanosheets, nanocubes and even cells...
October 10, 2016: Nature Nanotechnology
Charalampos G Pappas, Ramim Shafi, Ivan R Sasselli, Henry Siccardi, Tong Wang, Vishal Narang, Rinat Abzalimov, Nadeesha Wijerathne, Rein V Ulijn
Sequence-specific polymers, such as oligonucleotides and peptides, can be used as building blocks for functional supramolecular nanomaterials. The design and selection of suitable self-assembling sequences is, however, challenging because of the vast combinatorial space available. Here we report a methodology that allows the peptide sequence space to be searched for self-assembling structures. In this approach, unprotected homo- and heterodipeptides (including aromatic, aliphatic, polar and charged amino acids) are subjected to continuous enzymatic condensation, hydrolysis and sequence exchange to create a dynamic combinatorial peptide library...
October 3, 2016: Nature Nanotechnology
Valentin Flauraud, Massimo Mastrangeli, Gabriel D Bernasconi, Jeremy Butet, Duncan T L Alexander, Elmira Shahrabi, Olivier J F Martin, Juergen Brugger
Predetermined and selective placement of nanoparticles onto large-area substrates with nanometre-scale precision is essential to harness the unique properties of nanoparticle assemblies, in particular for functional optical and electro-optical nanodevices. Unfortunately, such high spatial organization is currently beyond the reach of top-down nanofabrication techniques alone. Here, we demonstrate that topographic features comprising lithographed funnelled traps and auxiliary sidewalls on a solid substrate can deterministically direct the capillary assembly of Au nanorods to attain simultaneous control of position, orientation and interparticle distance at the nanometre level...
October 3, 2016: Nature Nanotechnology
Thomas M Hermans
No abstract text is available yet for this article.
October 3, 2016: Nature Nanotechnology
Filip K Malinowski, Frederico Martins, Peter D Nissen, Edwin Barnes, Łukasz Cywiński, Mark S Rudner, Saeed Fallahi, Geoffrey C Gardner, Michael J Manfra, Charles M Marcus, Ferdinand Kuemmeth
Electron spins in gate-defined quantum dots provide a promising platform for quantum computation. In particular, spin-based quantum computing in gallium arsenide takes advantage of the high quality of semiconducting materials, reliability in fabricating arrays of quantum dots and accurate qubit operations. However, the effective magnetic noise arising from the hyperfine interaction with uncontrolled nuclear spins in the host lattice constitutes a major source of decoherence. Low-frequency nuclear noise, responsible for fast (10 ns) inhomogeneous dephasing, can be removed by echo techniques...
October 3, 2016: Nature Nanotechnology
Amy Tarangelo, Scott J Dixon
No abstract text is available yet for this article.
September 26, 2016: Nature Nanotechnology
Sung Eun Kim, Li Zhang, Kai Ma, Michelle Riegman, Feng Chen, Irina Ingold, Marcus Conrad, Melik Ziya Turker, Minghui Gao, Xuejun Jiang, Sebastien Monette, Mohan Pauliah, Mithat Gonen, Pat Zanzonico, Thomas Quinn, Ulrich Wiesner, Michelle S Bradbury, Michael Overholtzer
The design of cancer-targeting particles with precisely tuned physicochemical properties may enhance the delivery of therapeutics and access to pharmacological targets. However, a molecular-level understanding of the interactions driving the fate of nanomedicine in biological systems remains elusive. Here, we show that ultrasmall (<10 nm in diameter) poly(ethylene glycol)-coated silica nanoparticles, functionalized with melanoma-targeting peptides, can induce a form of programmed cell death known as ferroptosis in starved cancer cells and cancer-bearing mice...
September 26, 2016: Nature Nanotechnology
Saeid Zanganeh, Gregor Hutter, Ryan Spitler, Olga Lenkov, Morteza Mahmoudi, Aubie Shaw, Jukka Sakari Pajarinen, Hossein Nejadnik, Stuart Goodman, Michael Moseley, Lisa Marie Coussens, Heike Elisabeth Daldrup-Link
Until now, the Food and Drug Administration (FDA)-approved iron supplement ferumoxytol and other iron oxide nanoparticles have been used for treating iron deficiency, as contrast agents for magnetic resonance imaging and as drug carriers. Here, we show an intrinsic therapeutic effect of ferumoxytol on the growth of early mammary cancers, and lung cancer metastases in liver and lungs. In vitro, adenocarcinoma cells co-incubated with ferumoxytol and macrophages showed increased caspase-3 activity. Macrophages exposed to ferumoxytol displayed increased mRNA associated with pro-inflammatory Th1-type responses...
September 26, 2016: Nature Nanotechnology
Likai Li, Jonghwan Kim, Chenhao Jin, Guo Jun Ye, Diana Y Qiu, Felipe H da Jornada, Zhiwen Shi, Long Chen, Zuocheng Zhang, Fangyuan Yang, Kenji Watanabe, Takashi Taniguchi, Wencai Ren, Steven G Louie, Xian Hui Chen, Yuanbo Zhang, Feng Wang
Phosphorene, a single atomic layer of black phosphorus, has recently emerged as a new two-dimensional (2D) material that holds promise for electronic and photonic technologies. Here we experimentally demonstrate that the electronic structure of few-layer phosphorene varies significantly with the number of layers, in good agreement with theoretical predictions. The interband optical transitions cover a wide, technologically important spectral range from the visible to the mid-infrared. In addition, we observe strong photoluminescence in few-layer phosphorene at energies that closely match the absorption edge, indicating that they are direct bandgap semiconductors...
September 19, 2016: Nature Nanotechnology
Ingmar Jakobi, Philipp Neumann, Ya Wang, Durga Bhaktavatsala Rao Dasari, Fadi El Hallak, Muhammad Asif Bashir, Matthew Markham, Andrew Edmonds, Daniel Twitchen, Jörg Wrachtrup
The generation and control of fast switchable magnetic fields with large gradients on the nanoscale is of fundamental interest in material science and for a wide range of applications. However, it has not yet been possible to characterize those fields at high bandwidth with arbitrary orientations. Here, we measure the magnetic field generated by a hard-disk-drive write head with high spatial resolution and large bandwidth by coherent control of single electron and nuclear spins. We are able to derive field profiles from coherent spin Rabi oscillations close to the gigahertz range, measure magnetic field gradients on the order of 1 mT nm(-1) and the quantify axial and radial components of a static and dynamic magnetic field independent of its orientation...
September 12, 2016: Nature Nanotechnology
Sander A Mann, Sebastian Z Oener, Alessandro Cavalli, Jos E M Haverkort, Erik P A M Bakkers, Erik C Garnett
Nanophotonic engineering shows great potential for photovoltaics: the record conversion efficiencies of nanowire solar cells are increasing rapidly and the record open-circuit voltages are becoming comparable to the records for planar equivalents. Furthermore, it has been suggested that certain nanophotonic effects can reduce costs and increase efficiencies with respect to planar solar cells. These effects are particularly pronounced in single-nanowire devices, where two out of the three dimensions are subwavelength...
September 12, 2016: Nature Nanotechnology
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