International Conference on Condensed Matter Physics

A newly published study reveals that the Third Law of Thermodynamics can be restored in thin films of the magnetic material spin ice. A newly published study reveals that the Third Law of Thermodynamics can be restored in thin films of the magnetic material spin ice. A newly published study reveals that the Third Law of Thermodynamics can be restored in thin films of the magnetic material spin ice. In the familiar world around us it is always possible to make things colder, but science has established that there is a limit to how cold an object can be – the so-called `absolute zero’ of temperature, or minus 273 degrees centigrade At the absolute zero it is expected that the entropy of a substance, a measure of the randomness of the atoms within it, should itself be zero. The concept that absolute zero equates to zero entropy or randomness is called the Third Law of Thermodynamics. A famous exception to the Third Law is spin ice, in which atomic magnetic moments or `spins’ remain random...

High resolution X-ray diffraction patterns at in-situ applied electric fields, corresponding variation of lattice spaces with applied electric fields, and variation of magnetization at different electric fields and temepratures for the 0.58BiFeO3-0.42Bi0.5K0.5TiO3 single crystal. Credit: Yin Lihua A research team led by associate Prof. Yin Lihua from the Hefei Institutes of Physical Science of the Chinese Academy of Sciences has demonstrated a clear control of magnetism at low electric fields (E) at room temperature. The E-induced phase transformation and lattice distortion were found to lead to the E control of magnetism in multiferroic BiFeO3-based solid solutions near the morphotropic phase boundary (MPB). The study was published in Acta Materialia. Multiferroic materials, with magnetic and ferroelectric properties, are promising for multifunctional memory devices. Magnetoelectric-based control methods in insulating multiferroic materials require less energy and have potential for h...

Exploiting ultra-confined and highly directional polaritons at the nanoscale is essential for developing integrated nanophotonic devices, circuits and chips. High-symmetry crystals have been extensively studied, with a particular focus on hyperbolic polaritons (HPs). However, the in-plane HP propagation in high-symmetry optical crystals usually exhibits four mirror-symmetric beams, which reduces the directionality and energy-transporting efficiency. In a new paper published in eLight, a team of scientists led by Professor Xinliang Zhang and Peining Li from Huazhong University of Science and Technology and Professor Zhigao Dai from China University of Geosciences have developed a new technique for in-plane anisotropic excitation and propagation of HPs by controlling the near-field excitation source. Their research could expand the possibilities for manipulating asymmetric polaritons, where it could be applied to reconfigurable polaritonic devices. Recently, hyperbolic shear polaritons,...

  (Phys.org) —When a rubber ball and a droplet of water are compressed onto a solid surface, they behave very differently. For the ball, the compression process is reversible, so the ball retains its original form when decompressed. In contrast, the compression process for the water droplet is irreversible, and the droplet's contact angle with the surface irreversibly changes because of the way the droplet interacts with the surface's chemical or physical inhomogeneities. But now in a new study, physicists have shown that a droplet of liquid mercury can undergo a reversible compression process like a solid object does, as long as the surface it interacts with is "super-mercury-phobic." Such a surface is very resistant to mercury, so the mercury droplet does not spread out like a typical liquid droplet does. The physicists, Juan V. Escobar and Rolando Castillo at the National Autonomous University of Mexico in Mexico City, have published a paper on how a liquid can beh...

  Photons and electrons. Optoelectronic chips of the future may use transition metal silicides. Molecular beam epitaxy allows researchers to create thin slabs of materials with extremely precise control for use in the electronics industry and in basic physics research. A “substrate” crystal such as silicon serves as the base upon which atoms from a beam are deposited in layers. The deposited atoms tend to line up with those in the substrate, or at least in patterns strongly influenced by substrate atoms. Researchers have discovered many atomic configurations (“pseudomorphic phases”) that exist only in epitaxial films and not in the independently crystallized, or “bulk” material. Physical properties can differ dramatically between bulk and epitaxial phases. For example, some of the transition metal silicides are bulk semiconductors but become metals under appropriate thin film conditions. Researchers hope to exploit that property to make microscopic metallic connections to semicondu...

Dynamical heterogeneity, spatiotemporal fluctuations in local dynamical behavior, may explain the statistical mechanics of amorphous solids that are mechanically rigid but have a disordered structure similar to that of a dense liquid. From the point of view of statistical physics, glasses are mysterious materials. Glassy materials possess a mechanical rigidity, which is similar to that of a crystalline material. In a crystal, rigidity is a direct consequence of long-range periodic order: It is not possible to move a single particle in a perfect crystal (while preserving the crystalline order) without also moving an extensive set of neighbors [Fig. 1 (a)]. While mechanically rigid—glasses do not seem to be characterized by any type of long-range order, see Fig. (b)—they resemble ordinary dense liquids. The comparison between crystals and glasses suggests that perhaps a more subtle symmetry breaking takes place during the formation of a glass, one that is not obvious to the naked eye. T...

'Magic angle' twisted trilayer graphene doesn't only have an impressively exotic name, it might be a particularly rare type of superconductor, according to new research – one that could be useful everywhere from medical equipment to quantum computers. Scientists are finding that stacking single-atom layers of graphene on top of each other at slightly different angles can create new materials with exciting properties, which led to the recent discovery of magic-angle twisted trilayer graphene. Now, a new study from the same team shows that this material could be a "spin-triplet" superconductor – one that isn't affected by high magnetic fields – which potentially makes it even more useful. "The value of this experiment is what it teaches us about fundamental superconductivity, about how materials can behave, so that with those lessons learned, we can try to design principles for other materials which would be easier to manufacture, that could perhaps give yo...

For decades, it was thought that only two types of superconductors existed, but a new study has just uncovered a third. Wires don’t usually like being the bearers of electric current. While we find them extremely useful to light our houses, charge our phones, and heat water for our tea, they routinely manifest their opposition to the flow of electricity by heating up. Because of this effect, called electrical resistance, the energy dissipated as heat is wasted, and the amount of electric current that a wire can carry before it melts is limited. But a special kind of material is much happier to host electricity, so much so that under very low temperatures they do not exhibit any resistance. Superconductors, as they are known, don’t heat up at all and can thus carry much larger electric currents, which in turn makes them behave as extremely strong magnets. These superconducting magnets are part of MRI scanners, particle accelerators such as the ones at CERN, and the ultra-fast magnetic l...