Hedgehog spin textures

Magnetic skirmions are quasiparticles which present extended configurations (or textures) of spins and their physics are of great interest since they could be used in spintronics as sensors or memory storage devices. Its manipulation and tailoring is thus of great importance.

In a recent work published in Nanoscale, a group led by Prof. Agustina Asenjo, report the stabilization of half hedgehog skyrmionic configuration in permalloy hemispherical nanodots, induced by the stray field of the MFM probe.

As the first author, Eider Berganza, explains, “this is a remarkable achievement due to soft magnetic nature of the permalloy and the absence of the choice of the material, which does not present magnetocrystalline anisotropy or Dzyaloshinskii–Moriya interaction, considered as necessary ingredients for the nucleation of skyrmions”.

 

This research, has been a huge collaborative effort that involved sample preparation, measurements and theoretical micromagnetic simulations in Spain, Germany and the US.

This image we did under the supervision of Eider Berganza and Miriam Jaafar (ICMM-CSIC) has been featured in the Cover of Nanoscale. Personally, has been the apex of a long and beautiful collaboration with old friends.

 

Polariton condensates’ propagation.

Polaritons are versatile quasiparticles that could be at the core of new technologies, since polariton devices have been proposed, such as polariton lasers, optical gates, transistors, spin-based elements and integrated circuits. Yet, their propagation depends strongly on the geometry of the pathway laid for them.

In a recent paper, Luis Viña, Dolores MartĂ­n, et al. in a huge collaborative research (Madrid, Jena, WĂŒrzburg, Saint-Petersburg, Reykjavik and Saint Andrews) have analyzed the Impact of the energetic landscape on polariton condensates’ propagation along a coupler”, published in Advanced Optical Materials.



The amount of technical challenges involved in this research is hard to grasp: from the manufacture of the guides to the experimental measurements, that require literally “taking pictures of light”.

We did this picture that was featured in the cover of Advanced Optical Materials, under close supervision of Dolores Martín and Luis Viña.

 

Sound Vortices

At Phonometa (Christensen’s Research Group), they’re specialists in physical acoustics and they’re finding acoustic analogues to an amount of physical processes.

In their last published work they show that, in Dr. Christensen own words “a Majorana‐like bound state can be engineered in artificial acoustic lattices thanks to a Jackiw–Rossi vortex, which is the analog of a topological superconductor vortex. Such vortex is created by introducing a KekulĂ© texture to the man‐made lattice of rigid cylinders. We also show how this binding mechanism can be well explained by a topological pumping process comprising adiabatic variations of the cylinder radii, which concentrates strong acoustic energy to the lattice center as shown in the cover image”.

This picture we made to illustrate the process, and under close collaboration with Dr. Johan Christensen and Dr Penglin Gao, was featured in the front cover of Advanced Quantum Technologies.

Living electric wires

Materials scientists have for decades fantasized about using DNA as a structural element in electronic circuits. And for decades, the electrical properties of DNA have remain a mystery. Hundreds of different, controversial results have appeared in the literature… That ends today!

Researchers from Jerusalem, Tel Aviv, Michigan, Cyprus, Seville and Madrid, have reported the observation of “very high currents of tens of nanoamperes” through the backbone of DNA molecules. And what it is more interesting, this conduction occurs through great distances.

This observation has required the development of several techniques: a way to “grow” DNA attached to a gold nanoparticle and a way to trap this DNA using non uniform electric fields. In fact, these techniques are important on their own and whey could be the base for the development of a novel electronic bio sensor, highly sensitive to specific sequences of DNA of RNA.

We made this picture for Prof. Juan Carlos Cuevas (UAM) to illustrate these results published in Nature Nanotechnology.

 

Covalent organic frameworks

Covalent organic networks are usually synthesized on noble metal surfaces. It is widely understood that these metals have strong catalytic abilities. However, it is of great interest the use of nonmetallic surfaces in these kind of reactions.

At the NanoPhysics Lab (CMF, Gipuzkoa) they’re studying one of these routes to obtain covalent molecular systems on non-metallic substrates. In particular they’ve managed to understand and improve the synthesis of nanoribbons on TiO2 surfaces. They show that highly reduced surfaces (in opposition to stoichiometric TiO2) increases the reaction yield and improved polymer length.

We did this picture to artistically illustrate the process under the close supervision of Dr. Celia Rogero.

Graphene Design

The level of control chemistry is reaching in the synthesis of graphene is mind-blowing. At the Department of Physics in Basel University, together with the University of Bern, Warwick and Lancaster, nitrogen-doped porous graphene nanoribbons (N-GNRs) were synthesized for the first time.

These N-GNRs are ladder-like molecules whose crystal lattice contains both periodic pores and a regular pattern of nitrogen atoms. And interestingly, these molecules don’t behave as conductors, as graphene does, but as semiconductors, making them very attractive in electronic applications.

We did this picture to illustrate the synthesis of the N-GNRs on request of Prof. E. Meyer and under the close supervision of Dr. Shi-Xia Liu.

 

On circulenes, flatness and butterflies.

Circulene is a polycyclic aromatic hydrocarbon molecule composed by eight benzene rings. Because of geometric demands, the molecule adopts a saddle-shaped structure.This family of molecules, made of hexagonal and pentagonal rings are been studied for their promising applications in organic semiconductors, organic light-emitting diodes and liquid crystalline materials.

Prof. Shingo Ito et al. have just described the first example of a circulene bearing six hexagons and two pentagons which happens to have unique electronic structures, and intrinsic properties. In particular, they’ve proved this circulene to adopt a planar configuration.

This research, published in the Journal of American Chemical Society (JACS), was featured on the cover. The image was made under close supervision of Prof. Shigeky Kawai and Prof. Shingo Ito.

 

Heat: a 2D materials strain story

The Castellanos-GĂłmez Lab is an old friend of this website (and an old friend, period). And luckily for us, seems they never stop working at the highest level.

This time they bring to the table a new way to engineer the biaxial strain in 2D materials. Their approach has been to create a tiny loop (~100 ”m in diameter) and by passing a current through it they’re able to locally vary the temperature of a polymer and induce a highly controlled biaxial expansion of its surface. This tool will allow to study the effect of strain in 2D materials and represents an important breaktrough in the industrialization process of these materials. As doctor Yu Kyoung Ryu (first author of the paper) points out, “this is a new milestone on 2D materials straintronics”.

We made this picture at request of the group leader Dr. Andrés Castellanos to illustrate the device. Congratulations!

(On a side note, we also did this other picture, just for fun, and cause we like them!)

Strong coupling over large distances

It seems that quantum technologies never sleep. Researchers are bringing new improvements and solving impossible challenges every day. In this case the good news came from our friends at Basel University. Together with the University of Hanover they’ve came up with a way to produce a strong coupling between two quantum systems over a distance.

Strong coupling between quantum systems is essential for quantum technologies to work, for instance to create quantum networks. Until now, for two systems to be strongly coupled, they both needed to be really close and in highly controlled environments where they could interact via electrostatic or magnetostatic forces.

For the first time, a team of physicist led by Prof. Philipp Treutlein, form the Department of Physics at Basel University, has succeeded in the creation of a strong coupling between two systems at large distances and at room temperature. In particular, they’ve used laser light to couple the motion of the spin of atoms over 1 meter [read more].

We made this picture for them to illustrate the process. This research has been published in Science.

Glowing Lanthanides

It’s not the first time we bring these people to our website, and there are several reasons for that. First of all, they keep hiring us to make cool images for them. But the main reason is that they are doing amazing work in the field of chemical sensors.

These time Dr. Juan Cabanillas-Gonzalez and Dr. Jose Sanchez Costa, both at IMDEA Nanociencia (Spain) bring us “A novel gas sensing mechanism exploiting lanthanide luminescence modulation upon NO2 adsorption”. To make a long story short, this is a crystal that glows beautifully when NO2 is around.

This has not only useful practical applications in the detection of NO2 market; it would make a beautiful luminescence displays without requiring expensive electronics. “But it also provides understanding of the nature and effects of NO2 interactions within the MOFs and the signal transduction mechanism.” You can read more about it in their recent article.

The picture we did to illustrate this experiment was featured on the cover of the Journal of Physical Chemistry Letters.