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Editorial

Measuring impact p477

doi:10.1038/nmat3063

Citation analyses can condense scholarly output into numbers, but they do not live up to peer review in the evaluation of scientists. Online usage statistics and commenting could soon enable a more refined assessment of scientific impact.


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Interview

The best we have pp478 - 479

Interview with Pavel Exner

doi:10.1038/nmat3045

Pavel Exner, the newly elected Vice President of the European Research Council and Scientific Director of the Doppler Institute for Mathematical Physics and Applied Mathematics in Prague, talked to Nature Materials about his role in the European funding institution, the value of peer review in identifying the best scientists, the rise of science metrics and the challenges of running an efficient evaluation system.


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Research Highlights

Our choice from the recent literature p480

doi:10.1038/nmat3062


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News and Views

Solar energy: The thermoelectric alternative pp481 - 482

Jacob Karni

doi:10.1038/nmat3057

Results show that achievable improvements may make solar thermoelectric generators competitive with other solar power conversion methods.


Nanomedicine: Swarming towards the target pp482 - 483

Yucai Wang, Paige Brown & Younan Xia

doi:10.1038/nmat3060

A system comprising 'signalling' and 'receiving' modules — where the receiving module circulating in the bloodstream is directed to the tumour by a cascade triggered by the signalling module — improves the targeting effect of a nanomedicine.


Organic spintronics: Filtering spins with molecules pp484 - 485

Stefano Sanvito

doi:10.1038/nmat3061

Conventional magnetoresistive devices are composed of magnetic and non-magnetic films. It is now shown that, at low temperature, a carbon nanotube decorated with single-molecule magnets can function as an all-organic spin valve.


Material witness: Sink or swim p485

Philip Ball

doi:10.1038/nmat3056


Polymer electrolyte membranes: Diffusion realigned pp486 - 487

Edward T. Samulski

doi:10.1038/nmat3059

Stretching polymer electrolyte membranes increases water diffusion along the stretched direction. It is now shown that the enhancement in transport is a result of the alignment of domains of hydrophilic channels, and that transport anisotropy and alignment are linearly coupled.


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Letters

Direct tomography with chemical-bond contrast pp489 - 493

Simo Huotari, Tuomas Pylkkänen, Roberto Verbeni, Giulio Monaco & Keijo Hämäläinen

doi:10.1038/nmat3031

Although X-ray tomography has proven to be an efficient tool for three-dimensional imaging, its application to light materials has not been too successful. A new X-ray spectroscopy tomography method has now been developed that allows the mapping of chemical bonding in various types of structures, as well as the imaging of soft materials in three dimensions.

Subject terms: Characterisation and analytical techniques | Polymers


Arrays of indefinitely long uniform nanowires and nanotubes pp494 - 501

Mecit Yaman, Tural Khudiyev, Erol Ozgur, Mehmet Kanik, Ozan Aktas, Ekin O. Ozgur, Hakan Deniz, Enes Korkut & Mehmet Bayindir

doi:10.1038/nmat3038

Nanowires have many applications across a number of disciplines. So far, their length has been largely limited to mesoscale dimensions. Through the adaption of an iterative fibre-drawing process it is now possible to fabricate millions of ordered nanowires and nanotubes of almost infinite length.

Subject terms: Optical, photonic and optoelectronic materials | Nanoscale materials | Design synthesis and processing


Supramolecular spin valves pp502 - 506

M. Urdampilleta, S. Klyatskaya, J-P. Cleuziou, M. Ruben & W. Wernsdorfer

doi:10.1038/nmat3050

In macroscopic spin valves, the current between two magnetic electrodes can be tuned by external magnetic fields. Here, a molecular-scale spin valve is demonstrated in which a single-molecule magnet, through its localized magnetic moment, modulates the conductance of a single-walled carbon nanotube quantum dot with magnetoresistance ratios reaching 300%.

Subject terms: Electronic materials | Molecular electronics | Magnetic materials | Nanoscale materials

See also: News and Views by Sanvito


Linear coupling of alignment with transport in a polymer electrolyte membrane pp507 - 511

Jing Li, Jong Keun Park, Robert B. Moore & Louis A. Madsen

doi:10.1038/nmat3048

Polymer electrolyte membranes selectively transport ions and polar molecules, and are of interest for applications such as polymeric batteries, fuel cells, mechanical actuators and water purification. Transport anisotropy is now shown to linearly depend on the degree of alignment, indicating that membrane stretching only causes domain reorientation without affecting channel dimensions or defect structure.

Subject terms: Polymers | Materials for energy | Characterisation and analytical techniques

See also: News and Views by Samulski


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Articles

Structural origin of enhanced slow dynamics near a wall in glass-forming systems pp512 - 520

Keiji Watanabe, Takeshi Kawasaki & Hajime Tanaka

doi:10.1038/nmat3034

Container walls are known to have a significant influence on the dynamics of glass formation. Computations now suggest that structural order is the origin of the slower dynamics of a glass-forming liquid near container walls.

Subject terms: Glasses | Computation, modelling and theory


Giant Rashba-type spin splitting in bulk BiTeI pp521 - 526

K. Ishizaka, M. S. Bahramy, H. Murakawa, M. Sakano, T. Shimojima, T. Sonobe, K. Koizumi, S. Shin, H. Miyahara, A. Kimura, K. Miyamoto, T. Okuda, H. Namatame, M. Taniguchi, R. Arita, N. Nagaosa, K. Kobayashi, Y. Murakami, R. Kumai, Y. Kaneko, Y. Onose & Y. Tokura

doi:10.1038/nmat3051

A very large Rashba-type spin splitting, which is a consequence of spin–orbit interaction, has been observed in the heavy-element semiconductor BiTeI. The results show the possibility, in principle, of using the material in spintronics devices in which the electron spin is controlled by electric currents.

Subject terms: Semiconductors | Magnetic materials


Giant enhancement of spin accumulation and long-distance spin precession in metallic lateral spin valves pp527 - 531

Yasuhiro Fukuma, Le Wang, Hiroshi Idzuchi, Saburo Takahashi, Sadamichi Maekawa & YoshiChika Otani

doi:10.1038/nmat3046

Pure spin current—the flow of spin angular momentum involving no charge movement—could lead to highly efficient spintronic devices. It is now shown that through low-resistivity magnetic tunnelling junctions it is possible to induce spin accumulation in solid-state devices one hundred times higher than previously obtained. This is the main requirement for generation of large spin currents.

Subject terms: Magnetic materials | Electronic materials


High-performance flat-panel solar thermoelectric generators with high thermal concentration pp532 - 538

Daniel Kraemer, Bed Poudel, Hsien-Ping Feng, J. Christopher Caylor, Bo Yu, Xiao Yan, Yi Ma, Xiaowei Wang, Dezhi Wang, Andrew Muto, Kenneth McEnaney, Matteo Chiesa, Zhifeng Ren & Gang Chen

doi:10.1038/nmat3013

The conversion of sunlight into electricity has been dominated by photovoltaic and solar thermal power generation. A highly efficient solar to electric energy conversion device based on nanostructured thermoelectric materials and high solar concentration is now demonstrated. The results show potential for cost effective solar thermoelectric generation.

Subject terms: Polymers | Materials for energy | Electronic materials

See also: News and Views by Karni


Atomic layer-deposited tunnel oxide stabilizes silicon photoanodes for water oxidation pp539 - 544

Yi Wei Chen, Jonathan D. Prange, Simon Dühnen, Yohan Park, Marika Gunji, Christopher E. D. Chidsey & Paul C. McIntyre

doi:10.1038/nmat3047

Electrochemical energy can be produced by using solar energy to oxidize water, providing an abundant source of electrons, which are needed in fuel synthesis. The operation of an efficient and stable semiconductor nanocomposite anode, made of a protective TiO2 layer that protects a silicon substrate during photoelectrochemical water oxidation in both dark and light conditions, is now reported.

Subject terms: Materials for energy | Surface and thin films


Nanoparticles that communicate in vivo to amplify tumour targeting pp545 - 552

Geoffrey von Maltzahn, Ji-Ho Park, Kevin Y. Lin, Neetu Singh, Christian Schwöppe, Rolf Mesters, Wolfgang E. Berdel, Erkki Ruoslahti, Michael J. Sailor & Sangeeta N. Bhatia

doi:10.1038/nmat3049

A two-component nanoparticle system that communicates and enhances in vivo drug delivery and diagnostics has been devised. The system comprises ‘signalling’ nanoparticles that target tumours and then broadcast the tumour’s location to ’receiving’ nanoparticles in circulation, which carry therapeutic or diagnostic cargos, hence amplifying tumour targeting.

Subject terms: Biomedical materials | Nanoscale materials

See also: News and Views by Wang et al.


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