Condensed-matter physics

Letter | 28 November 2012

Observing the drop of resistance in the flow of a superfluid Fermi gas

Direct measurements of the conduction properties of strongly interacting ultracold fermions reveal the well-known drop of resistance associated with the onset of superfluidity.

David Stadler
, Sebastian Krinner
& Tilman Esslinger

Research Highlights | 31 October 2012

Proponent of supersolid helium joins sceptics

Physicist Moses Chan, who in 2004 published evidence for supersolidity, explains how he came to doubt his own discovery.

Eugenie Samuel Reich

News & Views | 19 September 2012

By tailoring the architecture of a bulk material at several different length scales, the ability of a semiconductor to convert heat into voltage has been optimized to a groundbreaking level of performance. See Letter p.414

Tom Nilges

News & Views | 19 September 2012

Spinning towards scalable circuits

Silicon devices form the backbone of modern computers. It turns out that they might also be a natural hardware platform for a new era of computing technology that uses the principles of quantum physics. See Letter p.541

Lee C. Bassett
& David D. Awschalom

Letter | 19 September 2012

High-performance bulk thermoelectrics with all-scale hierarchical architectures

Controlling the structure of thermoelectric materials on all length scales (atomic, nanoscale and mesoscale) relevant for phonon scattering makes it possible to increase the dimensionless figure of merit to more than two, which could allow for the recovery of a significant fraction of waste heat with which to produce electricity.

Kanishka Biswas
, Jiaqing He
& Mercouri G. Kanatzidis

Letter | 19 September 2012

A single-atom electron spin qubit in silicon

The coherent manipulation of an individual electron spin qubit bound to a single phosphorus donor atom in natural silicon provides an excellent platform on which to build a scalable quantum computer.

Jarryd J. Pla
, Kuan Y. Tan
& Andrea Morello

News | 18 September 2012

'Tantalizing' hints of room-temperature superconductivity

Doped graphite may superconduct at more than 100 ºC.

Edwin Cartlidge

Letter | 12 September 2012

Stabilization of Leidenfrost vapour layer by textured superhydrophobic surfaces

Textured superhydrophobic surfaces—well known for their water-repelling properties—can be used to control the boiling state of a liquid in contact with a hot surface, suppressing the unwanted nucleation of bubbles.

Ivan U. Vakarelski
, Neelesh A. Patankar
& Sigurdur T. Thoroddsen

Letter | 05 September 2012

Flexible metal-oxide devices made by room-temperature photochemical activation of sol–gel films

A method for annealing metal-oxide semiconductor films with deep-ultraviolet light yields thin-film transistors with performance comparable to that of thermally annealed devices, and widens the range of substrates on which such devices can be fabricated.

Yong-Hoon Kim
, Jae-Sang Heo
& Sung Kyu Park

Letter | 22 August 2012

Room-temperature ferroelectricity in supramolecular networks of charge-transfer complexes

Organic ferroelectrics with switchable electrical polarization would be an attractive prospect for applications if their Curie temperature—below which these materials display ferroelectric behaviour—could be raised to room temperature or above; this goal has now been achieved with a family of organic materials characterized by a supramolecular structural motif.

Alok S. Tayi
, Alexander K. Shveyd
& Samuel I. Stupp

Letter | 15 August 2012

Electronic read-out of a single nuclear spin using a molecular spin transistor

The long-lived nuclear spin state of an individual metal atom embedded in a single-molecule magnet is shown to be readable electronically.

Romain Vincent
, Svetlana Klyatskaya
& Franck Balestro

Letter | 11 July 2012

Giant spin Seebeck effect in a non-magnetic material

A giant spin Seebeck effect—three orders of magnitude greater than previously detected—has been observed in a non-magnetic material, InSb; the proposed mechanism relies only on phonon drag and spin–orbit interactions in a spin-polarized system, not on magnetic exchange.

C. M. Jaworski
, R. C. Myers
& J. P. Heremans

Letter | 11 July 2012

Terahertz-field-induced insulator-to-metal transition in vanadium dioxide metamaterial

An innovative technique uses ultrafast below-bandgap electric-field pulses to induce and probe an insulator–metal transition in an oxide thin film on which a metamaterial structure has been deposited.

Mengkun Liu
, Harold Y. Hwang
& Richard D. Averitt

Letter | 20 June 2012

Electronic nematicity above the structural and superconducting transition in BaFe₂(As_1−xP _x )₂

Electronic nematicity, a unidirectional self-organized state that breaks the rotational symmetry of the underlying lattice, has been observed in an iron-based superconductor, BaFe₂(As_1−xP _x )₂, over a wide range of phosphorus concentration, resulting in a phase diagram similar to the pseudogap phase diagram of the copper oxides.

S. Kasahara
, H. J. Shi
& Y. Matsuda

News & Views | 13 June 2012

Majorana modes materialize

Elusive theoretical fantasies known as Majorana modes have been observed in a hybrid semiconductor–superconductor system. These emergent exotica open up promising prospects for quantum computation.

Frank Wilczek

News & Views | 23 May 2012

Repulsive polarons found

Quasiparticles known as repulsive polarons are predicted to occur when 'impurity' fermionic particles interact repulsively with a fermionic environment. They have now been detected in two widely differing systems. See Letters p.615 & p.619

Peter Hannaford

News & Views | 23 May 2012

Molecules meet materials

An inorganic semiconductor can take the place of the liquid electrolyte typically used in dye-sensitized solar cells. This achievement points the way to making these devices more easily manufactured and more stable. See Letter p.486

Thomas E. Mallouk

Letter | 23 May 2012

Attractive and repulsive Fermi polarons in two dimensions

Investigations of a two-dimensional spin-imbalanced Fermi gas reveal the existence of the Fermi polaron for attractive and repulsive interactions, and the transition from the attractive polaron to a molecule.

Marco Koschorreck
, Daniel Pertot
& Michael Köhl

Letter | 23 May 2012

All-solid-state dye-sensitized solar cells with high efficiency

A solution-processable inorganic semiconductor is reported that can replace the liquid electrolyte of dye-sensitized solar cells, yielding all-solid-state solar cells with impressive energy conversion efficiencies.

In Chung
, Byunghong Lee
& Mercouri G. Kanatzidis

News & Views | 16 May 2012

Geomagnetism under scrutiny

New calculations show that the electrical resistance of Earth's liquid-iron core is lower than had been thought. The results prompt a reassessment of how the planet's magnetic field has been generated and maintained over time. See Letter p.355

Bruce Buffett

Letter | 09 May 2012

Patterning by controlled cracking

Propagating cracks—normally associated with material failure and viewed as undesirable—can be controlled in a film/substrate system, opening up new possibilities for nanofabrication and atomic-scale patterning.

Koo Hyun Nam
, Il H. Park
& Seung Hwan Ko

Letter | 02 May 2012

Liquid-crystal-mediated self-assembly at nanodroplet interfaces

Ordering in liquid-crystal applications is usually achieved using surfactants, but here, in modelled nanodroplets of liquid crystals and surfactants, the liquid crystals control the ordering effects, which resemble those seen in block copolymer ordering, such as spots and stripes.

J. A. Moreno-Razo
, E. J. Sambriski
& J. J. de Pablo

News | 26 April 2012

Pigeons may ‘hear’ magnetic fields

The science of birds’ magnetic sense grows more complicated.

Daniel Cressey

Letter | 25 April 2012

Thermal and electrical transport across a magnetic quantum critical point

The heavy-fermion compound YbRh₂Si₂ possesses a quantum critical point, at which the standard theory of electron behaviour in metals is expected to break down; such anomalous behaviour has now been observed.

Heike Pfau
, Stefanie Hartmann
& Frank Steglich

Letter | 25 April 2012

Engineered two-dimensional Ising interactions in a trapped-ion quantum simulator with hundreds of spins

A trapped-ion quantum simulator is used to demonstrate tunable long-range spin-spin couplings in two dimensions, relevant to studies of quantum magnetism at a scale that is intractable for classical computers.

Joseph W. Britton
, Brian C. Sawyer
& John J. Bollinger

News & Views | 18 April 2012

Electrons do the split

Interacting electrons that are confined to move in a one-dimensional structure do not simply jam together like cars in rush hour. Inelastic X-ray scattering shows that the electrons act as if they split into separate fractional entities. See Letter p.82

Ralph Claessen

News | 18 April 2012

Not-quite-so elementary, my dear electron

Fundamental particle ‘splits’ into quasiparticles, including the new ‘orbiton’.

Zeeya Merali

Letter | 18 April 2012

Coherent quantum phase slip

The magnetic-flux analogue to coherent Josephson tunnelling of electric charge has been observed in a strongly disordered superconducting nanowire.

O. V. Astafiev
, L. B. Ioffe
& J. S. Tsai

Letter | 18 April 2012

Spin–orbital separation in the quasi-one-dimensional Mott insulator Sr₂CuO₃

The splitting of the electron into distinct quasi-particles separately carrying the elementary particles’ spin and orbital angular momentum is observed in a one-dimensional Mott insulator.

J. Schlappa
, K. Wohlfeld
& T. Schmitt

Letter | 11 April 2012

Layered boron nitride as a release layer for mechanical transfer of GaN-based devices

Introducing an extremely thin layer of boron nitride between a sapphire substrate and the gallium nitride semiconductor grown on it is shown to facilitate the transfer of the resulting nitride structures to more flexible and affordable substrates.

Yasuyuki Kobayashi
, Kazuhide Kumakura
& Toshiki Makimoto

News & Views | 28 March 2012

Terahertz collisions

Intense laser fields can rip electrons from an atom and slam them back into it. By using intense terahertz radiation, this idea can be extended to electrons paired with 'holes' in a semiconductor. See Letter p.580

Rupert Huber

Letter | 28 March 2012

Observation of a roton collective mode in a two-dimensional Fermi liquid

Neutron scattering measurements of a monolayer of liquid ³He reveal an unexpected collective excitation at high wavevectors, which is described well by a dynamic many-body theory of Fermi liquids.

Henri Godfrin
, Matthias Meschke
& Martin Panholzer

News | 22 March 2012

‘Antimagnet’ renders magnets invisible

Magnetic cloak could bring medical benefits — and security risks.

Jon Cartwright

News & Views | 14 March 2012

A duo of graphene mimics

The synthesis of analogues of graphene by two different means provides insight into the origins of massless particles and paves the way for studies of materials with exotic topological properties. See Letters p.302 & p.306

Jonathan Simon
& Markus Greiner

Letter | 07 March 2012

Field-driven photoemission from nanostructures quenches the quiver motion

Experiments using ultrafast mid-infrared light pulses on nanostructures access a new regime in photoelectron emission, revealing classical sub-cycle electron dynamics in optical near-fields and breaking a diffraction limit in strong-field physics.

G. Herink
, D. R. Solli
& C. Ropers

News | 22 February 2012

Superconductor breaks high-temperature record

Iron-based crystal regains conducting properties under pressure.

Zeeya Merali

Letter | 22 February 2012

Re-emerging superconductivity at 48 kelvin in iron chalcogenides

Unexpectedly, in superconducting iron chalcogenides, a second, much higher, maximum in the superconducting transition temperature emerges under increasing pressure.

Liling Sun
, Xiao-Jia Chen
& Zhongxian Zhao

Research Highlights | 25 January 2012

Circuit, heal thyself

News & Views | 21 December 2011

A fresh twist on shrinking materials

Unusual lattice vibrations have been discovered in scandium trifluoride — a simple compound that shrinks when heated. This finding may help to explain the phenomenon of negative thermal expansion.

J. Paul Attfield

Letter | 21 December 2011

Tuning charge transport in solution-sheared organic semiconductors using lattice strain

A solution-processing method known as solution shearing is used to introduce lattice strain to organic semiconductors, thus improving charge carrier mobility.

Gaurav Giri
, Eric Verploegen
& Zhenan Bao

Letter | 30 November 2011

Observation of a pairing pseudogap in a two-dimensional Fermi gas

Observation of a many-body pairing gap in a trapped, 2D atomic Fermi gas shows that ultracold atomic gases can be used to emulate the physics of correlated 2D superconductors, with the ultimate goal of understanding high-temperature superconductivity.