Volume 13 Issue 7, July 2017

Ferroelectricity and superconductivity do not have much in common. Now, a superconducting and a ferroelectric-like state have been found to coexist in a doped perovskite oxide.

A device with superconducting contacts connected to graphene in the quantum Hall regime hints at a novel Andreev scattering mechanism.

The shorter the antenna, the higher the frequency — so what happens when nanoantennas hit optical frequencies? One answer may lead to high-harmonic generation without the need for high-powered lasers.

Solid-state systems capable of simulating the theoretical predictions of condensed matter are in short supply. Demonstrations of electronic Lieb lattices using two different platforms suggest this may be about to change.

Two studies show evidence that single layers of a transition metal dichalcogenide are two-dimensional topological insulators.

A curious peak in the distribution describing stochastic switching in bacterial motility had researchers confounded. But a careful study performed under varying mechanical conditions has now revealed that the breaking of detailed balance is to blame.

An inelastic neutron scattering study of the two-dimensional antiferromagnet Ca₂RuO₄ reveals evidence for a condensed-matter analogue of the Higgs mode, and its subsequent decay into transverse Goldstone modes.

The presence of a Higgs amplitude mode is revealed in a two-dimensional spin-half quantum antiferromagnet, C₉H₁₈N₂CuBr₄ by means of neutron scattering.

Slight changes in SrTiO’s nominal composition make it superconducting or ferroelectric. A compositional window for which the two phases exist is now reported; varying the fraction of Ca replacing Sr changes the superconducting critical temperature.

An excited two-level system emits a single photon, but in special circumstances it can emit two. The reason for this unexpected two-photon emission lies with modified Rabi oscillations.

Single photons stored in the collective Rydberg excitations of two atomic ensembles can interact with each other despite being micrometres apart.

High-harmonic emission from crystalline silicon can be made ten times brighter by exploiting local plasmonic fields in arrays of nano-antennas.

Measuring vector quantities in nanoscale systems is challenging — often only scalar magnitudes can be experimentally obtained. Now, a multi-frequency atomic force microscopy method for probing the 3D force response of a Ge(001) surface is reported.

Individual vacancies in a chlorine monolayer on copper can be manipulated with scanning tunnelling microscopy to engineer artificial lattices that have topologically nontrivial electronic states.

Individual carbon monoxide molecules on a copper surface can be manipulated with scanning tunnelling microscopy to realize an electronic Lieb lattice.

Experiments showing that a single layer of WTe₂ can conduct electricity along its edges while insulating in the interior suggests that this material is a two-dimensional topological insulator.

A combination of photoemission and scanning tunnelling spectroscopy measurements provide compelling evidence that single layers of 1T'-WTe₂ are a class of quantum spin Hall insulator.

Picosecond pulses of terahertz radiation induce non-equilibrium electron dynamics in a GaAs quantum Hall system, suppressing the longitudinal resistivity, and giving rise to a quantized transverse component.

A superconductor–graphene junction is shown to exhibit the quantum Hall effect, with the chemical potential of the edge state displaying a sign reversal. Such a system could provide a platform for observing isolated non-Abelian anyonic zero modes.

Products from ultracold atom–dimer exothermic reactions can be directly observed by controlling the energy released during the process, bringing the study of chemical dynamics to the quantum level.

Can short-range repulsion alone bring a system into the ferromagnetic phase? The question is explored by investigating the spin dynamics in a resonantly interacting ultracold Fermi gas, and a Stoner-like ferromagnetic instability is observed.

Flagellated bacteria move by alternately rotating their flagella clockwise and counterclockwise with dynamics that are shown here to be torque dependent. This non-equilibrium effect increases motor sensitivity as the torque increases.

The path to consistent cgs magnetic units has been long and winding, as is the process of universally adopting SI units. Andreas Trabesinger peeks into the history of the field.