Table of contents

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Crystallography matters p757


Celebrating a field of remarkable depth and importance.



The hidden structure of liquids pp758 - 759

Philip Ball


From its earliest days, crystallography has been viewed as a means to probe order in matter. J. D. Bernal's work on the structure of water reframed it as a means of examining the extent to which matter can be regarded as orderly.

Crystallography with powders pp760 - 762

Anthony K. Cheetham & Andrew L. Goodwin


Over the course of its long history, powder diffraction has provided countless insights into the properties of materials. It will continue to do so in the future, but with an emphasis on elucidating how materials respond to external stimuli.

Neutron scattering from quantum condensed matter pp763 - 767

Steven T. Bramwell & Bernhard Keimer


Collective quantum phenomena such as magnetism, superfluidity and superconductivity have been pre-eminent themes of condensed-matter physics in the past century. Neutron scattering has provided unique insights into the microscopic origin of these phenomena.

Reinventing neutron science in Europe pp767 - 768

Dimitri N. Argyriou


Neutron science has been a remarkable success story for European research. For this to continue, scientists need to be prepared to forge new networks and technologies.


News and Views

Spin waves: Close-up on spin dynamics pp770 - 771

Stanislas Rohart & Guillemin Rodary


Standing spin-waves can be excited in artificial chains of magnetic atoms using inelastic electron tunnelling spectroscopy, thereby offering a route to speed up the switching of their magnetization.

See also: Letter by Spinelli et al.

Material witness: Cutting-edge metallurgy p771

Philip Ball


Quantum dot solar cells: The surface plays a core role pp772 - 773

Delia J. Milliron


Mastering the impact of surface chemistry on the electronic properties and stability of colloidal quantum dots enables the realization of architectures with enhanced photovoltaic performance and air stability.

See also: Letter by Chuang et al. | Article by Ning et al.

Organic electronics: Addressing challenges pp773 - 775

John E. Anthony


Although promising, the use of organic semiconductors has not yet revolutionized consumer electronics. Synthesis of high-performance materials, enhanced control of morphology and smart exploitation of unique photophysical phenomena are the way forward to overcome the technological hurdles of this field.

Materials for bioelectronics: Organic electronics meets biology pp775 - 776

Guglielmo Lanzani


The structural similarity of organic semiconductors to biological compounds suggests the use of these materials in biomedical applications, yet their implementation is not straightforward. Research in this area is growing fast, thanks to the combined efforts of the multidisciplinary bioelectronics community.



Heavy-fermion quantum criticality and destruction of the Kondo effect in a nickel oxypnictide pp777 - 781

Yongkang Luo, Leonid Pourovskii, S. E. Rowley, Yuke Li, Chunmu Feng, Antoine Georges, Jianhui Dai, Guanghan Cao, Zhu’an Xu, Qimiao Si & N. P. Ong


Transitions between stable quantum phases of matter typically involve going through an unstable quantum critical point, the unique properties of which have become a focus of research in the past decade or so. Extensive bulk measurements on the nickel oxypnictide system CeNiAsO uncover heavy-fermion behaviour, suggesting the family of oxipnictides may be ideal materials for examining quantum criticality more broadly.

Imaging of spin waves in atomically designed nanomagnets pp782 - 785

A. Spinelli, B. Bryant, F. Delgado, J. Fernández-Rossier & A. F. Otte


The excitations that determine the low-temperature properties of ferromagnetic materials are called spin waves. Using a combination of inelastic electron tunnelling spectroscopy and numerical simulations, the spin waves occurring in a one-dimensional chain of iron atoms deposited on Cu2N are now imaged, and their dynamics examined.

See also: News and Views by Rohart & Rodary

Electric field control of soliton motion and stacking in trilayer graphene pp786 - 789

Matthew Yankowitz, Joel I-Jan Wang, A. Glen Birdwell, Yu-An Chen, K. Watanabe, T. Taniguchi, Philippe Jacquod, Pablo San-Jose, Pablo Jarillo-Herrero & Brian J. LeRoy


Trilayer graphene can be realized in two different stacking configurations, known as rhombohedral and Bernal stackings, which display different electronic characteristics. It is now shown that an applied perpendicular electric field can be used to switch between these two configurations.

Spin voltage generation through optical excitation of complementary spin populations pp790 - 795

Federico Bottegoni, Michele Celebrano, Monica Bollani, Paolo Biagioni, Giovanni Isella, Franco Ciccacci & Marco Finazzi


The combination of photonic and spintronic devices offers significant promise for optoelectronic applications. In analogy to a photovoltaic cell, an optoelectronic device that spatially separates electrons with opposite spin orientations on absorption of circularly polarized light is now demonstrated.

Improved performance and stability in quantum dot solar cells through band alignment engineering pp796 - 801

Chia-Hao M. Chuang, Patrick R. Brown, Vladimir Bulović & Moungi G. Bawendi


Fabricating low-temperature solution-processed solar cells with good power-conversion efficiency and stability in ambient conditions has proved challenging. The use of ligands that protect colloidal quantum dots from degradation in air and tune their energy levels is now shown to be a viable approach for the realization of spin-coated solar cells with very high efficiency.

See also: News and Views by Milliron

Hydrogen storage in Pd nanocrystals covered with a metal–organic framework pp802 - 806

Guangqin Li, Hirokazu Kobayashi, Jared M. Taylor, Ryuichi Ikeda, Yoshiki Kubota, Kenichi Kato, Masaki Takata, Tomokazu Yamamoto, Shoichi Toh, Syo Matsumura & Hiroshi Kitagawa


Palladium is of practical use as a hydrogen-storage metal and an effective catalyst for reactions related to hydrogen in a variety of industrial processes. Enhanced capacity and speed of hydrogen storage is now reported in Pd nanocrystals covered with a metal–organic framework.

Hydrogen-bonded structure and mechanical chiral response of a silver nanoparticle superlattice pp807 - 811

Bokwon Yoon, W. D. Luedtke, Robert N. Barnett, Jianping Gao, Anil Desireddy, Brian E. Conn, Terry Bigioni & Uzi Landman


Self-assembled nanoparticle superlattices, which consist of inorganic cores capped by organic ligands, can show emergent behaviour as a result of the coupling between their nanoscale components. The atom-level structure of a silver nanoparticle superlattice, deduced from X-ray imaging and simulations, is now reported as well as its response to hydrostatic compression, which involves anomalous pressure softening and correlated chiral rotation of the nanoparticles.

Internal dynamics of a supramolecular nanofibre pp812 - 816

Julia H. Ortony, Christina J. Newcomb, John B. Matson, Liam C. Palmer, Peter E. Doan, Brian M. Hoffman & Samuel I. Stupp


Variations in the internal conformational dynamics of supramolecular nanostructures may be important for their function, yet such dynamics have been difficult to probe experimentally. Now, the molecular motion through a nanofibre cross-section at subnanometre resolution has been quantified using site-directed spin labelling and electron paramagnetic resonance spectroscopy.

Stretchable liquid-crystal blue-phase gels pp817 - 821

F. Castles, S. M. Morris, J. M. C. Hung, M. M. Qasim, A. D. Wright, S. Nosheen, S. S. Choi, B. I. Outram, S. J. Elston, C. Burgess, L. Hill, T. D. Wilkinson & H. J. Coles


Liquid-crystalline elastomers combine rubber-like elasticity with the optical properties of liquid crystals, yet some of their properties depend on the particular liquid-crystal phase. Now, stretchable gels of the liquid-crystalline blue-phase I are reported. The blue-phase gels are electro-optically switchable under a moderate applied voltage, and their optical properties can be manipulated by an applied strain.



Air-stable n-type colloidal quantum dot solids pp822 - 828

Zhijun Ning, Oleksandr Voznyy, Jun Pan, Sjoerd Hoogland, Valerio Adinolfi, Jixian Xu, Min Li, Ahmad R. Kirmani, Jon-Paul Sun, James Minor, Kyle W. Kemp, Haopeng Dong, Lisa Rollny, André Labelle, Graham Carey, Brandon Sutherland, Ian Hill, Aram Amassian, Huan Liu, Jiang Tang, Osman M. Bakr & Edward H. Sargent


Although several techniques have been reported to obtain electron-rich colloidal quantum dots, these materials usually suffer from poor stability under air exposure. It is now shown that the use of strongly bound ligands and a careful ligands-exchange strategy lead to air-stable n-type quantum dots that can be used in solar cells and chemical sensors.

See also: News and Views by Milliron

Gradated assembly of multiple proteins into supramolecular nanomaterials pp829 - 836

Gregory A. Hudalla, Tao Sun, Joshua Z. Gasiorowski, Huifang Han, Ye F. Tian, Anita S. Chong & Joel H. Collier


Peptide-based nanofibres with bioactive proteins attached can now be made such that the protein ligands are introduced in a controlled manner. This tailoring of the nanofibre’s composition enables the ratio of multiple different proteins to be highly tuned within the assemblies. By changing the protein content of the nanofibres, it is possible to adjust the antibody responses in mice to the different nanofibres.