Articles in 2019

Quantifying the entropic effects of confined polymers in biological environments or single molecule experiments is a challenging task. Using the same strategy as the chemical potential of solutions, the authors derive a simple entropic force formula, which largely reduces that difficulty and clarifies several recent experiments in confined polymers.

Topological superconductors possess Majorana modes at the edge and are important in future quantum computational devices. The authors theoretically demonstrate the Larkin-Ovchinnikov superconducting phase can be topologically non-trivial in certain sandwich structure or iron-based superconductor films and possess a chain of Majorana modes.

Single layers of transition metal dichalcogenides are expected to be suitable for a number of applications and by stacking layers of different materials on top of each other (heterostructures) an even richer variety of properties can be explored. To this end the authors theoretically investigate cross material exciton states in a heterostructures of MoSe₂ and WSe₂ layers.

Vibration is a promising source of renewable energy, but to be of use it must be efficiently converted into electrical energy. In this paper, the authors propose a poly-stable energy harvesting approach for achieving synergetic multistable vibration which does not rely on external magnetic fields.

Negative capacitance describes a phenomenon where the increase in the charge of the capacitor results in decreasing its voltage. The authors put forth a ferroelectric nanodot harboring two polarization domains which stabilize static reversible negative capacitance.

Spin torque nano-oscillators are important candidates for several device applications. The authors demonstrate that the combination of two excitation methods, spin-polarised tunnelling current and pure spin Hall current, allows them to achieve greater injected spin current densities and power output than by each individual mechanism.

Communications Physics celebrates its first year anniversary of publishing research advances across the physical sciences. We take this opportunity to look back at what we achieved so far and our ambitions for the future.

Plasmonic nanostructures may provide a way to further enhance the strong light-matter coupling in 2D materials. In this paper, the authors use Raman spectroscopy to characterize the charge transfer, temperature, and strain of an individual gold nanoparticle on a sheet of graphene.

The intriguing coexistence of superconductivity and magnetism is examined via first-principle calculations in an iron-based superconductor. By calculating the RKKY interaction and bared susceptibility, the authors explained the unchanged Curie temperature and largely suppressed superconducting temperature upon doping observed in experiment.

Research on spin qubit systems for use in quantum computational devices has recently focused on the use of hole spins rather than the conventional single electron spins. The authors report the spin relaxation time of a single hole by developing a novel spin-sensitive charge-latching technique using a GaAs gated double quantum dot device.

Disproving hidden variables is a fundamental test for the validity of quantum mechanics and its nonlocal features. In this work, the authors consider a refined model where the spin magnitudes are conserved. In this way they can show a violation of the hidden variable model by a wider class of quantum states.

The origin of the superconductivity in iron-based superconductors remains elusive and whether a mechanism which describes all members can be found is under constant study. Using Raman spectroscopy the authors investigate magnetic ordering in FeSe, and further demonstrate that its properties are distinct among the iron-based superconductors.

Artificial spin ices are nanoscale frustrated lattices that mimic many of the properties seen in bulk frustrated materials. In this study, a new method is used to produce a 3D nanostructured frustrated lattice. Magnetic microscopy and simulations are then used to elucidate its underlying spin texture.

The successful isolation of a single layer of graphene has led to great interest in finding other 2D materials with similar electronic characteristics with additional spin-dependent phenomena. In this work, a 2D allotrope of Sn is grown on an Au(111) surface and shown through angle-resolved photoemission spectroscopy to have a linear band dispersion at the zone center and anti-parallel spin polarization.

The Pauli exclusion principle can be formulated in a generalized form where additional constraints are imposed to the orbital degrees of freedom of electrons. In this work these constraints are experimentally verified on a five qubit quantum computer with an error of one part in one quintillion.

An understanding of charge dynamics and direct observations of charge generation, transfer and recombination is important to help develop and apply various materials for electronic devices. The authors develop a time-resolved electrostatic force microscopy technique to visually observe charge migration on the nanoscale at a sub-microsecond timeframe.

The properties of strongly correlated materials have been successfully studied via ultrafast dynamics methods. The authors present combined experimental and theoretical results of photo-excitation of LaCoO₃ to probe the mechanisms at play behind the semiconductor-to-metal transition at high temperature.

The security of communications networks is a fundamental challenge of the current era, particularly with the move towards quantum communications. The authors perform joint transmission of quantum key distribution and up to 100 classical communication channels in the same fiber and report an average secret key rate of 27.2 kbit/s over a 24 h operation period where the classical data rate amounted to 18.3 Tbit/s.

Magnetorotational Instability (MRI) has long been considered a possible mechanism to transport angular momentum allowing fast accretion in astrophysical objects, but its standard form with a vertical magnetic field has never been experimentally verified. The authors present an experimental demonstration of a spring-mass analogue of the standard MRI using water as working fluid and a spring to mimic the action of magnetic fields.