Science Daily January 4, 2021 An international team of researchers (Austria, Switzerland) created supersolids using ultracold quantum gases of highly magnetic lanthanide atoms. This state of matter is solid and liquid at the same time. Due to quantum effects, a very cold gas of atoms can spontaneously develop both a crystalline order of a solid crystal and particle flow like a superfluid quantum liquid. A dipolar supersolid can be imagined as a chain of quantum droplets which communicate with each other via a superfluid background bath. They found that if the superfluid bath between the droplets is drained by control […]
Category Archives: Advanced materials
Chemists convert plastic bottle waste into insecticide sorbent
Phys.org December 23, 2020 An international team of researchers (Russia, China, Czech Republic, South Korea) created a sorbent that belongs to metal-organic frameworks, for imidacloprid insecticide removal from water. They developed a method to synthesize a metal-organic framework named UiO-66 with zirconium ions. The framework is sensitive to imidacloprid and due to its porosity and physicochemical properties, it attracts insecticide molecules removing them from water. In tests effective water purification took 15 grams of sorbent per liter. The sorbent may be reused several times. They reached up to five cycles during experiments. In the future the sorbent can be used […]
Physics breakthrough of the year
EurekAlert December 17, 2020 Silicon crystallized in the usual cubic (diamond) lattice structure has dominated the electronics industry for more than half a century. However, cubic silicon, germanium and SiGe alloys are all indirect-bandgap semiconductors that cannot emit light efficiently. An international team of researchers (Canada, the Netherlands, Germany, Austria) has demonstrated efficient light emission from direct-bandgap hexagonal Ge and SiGe alloys. They measured a sub-nanosecond, temperature-insensitive radiative recombination lifetime and observed an emission yield similar to that of direct-bandgap group-III–V semiconductors. They demonstrated that, by controlling the composition of the hexagonal SiGe alloy, the emission wavelength can be continuously […]
Physics discovery leads to ballistic optical materials
Nanowerk December 14, 2020 The mismatch between electronic systems and optical systems means that every time a signal converts from one to the other, inefficiency creeps into the system. A team of researchers in the US (UT Austin, UMass Lowell, Purdue University) has found a way to create more efficient metamaterials using semiconductors and a novel aspect of physics that amplifies the activity of electrons. They have demonstrated optical phenomenon of “ballistic resonance” resulting from the interplay between free charge motion in confining geometries and periodic driving electromagnetic fields, which can be utilized to achieve negative permittivity at frequencies well […]
UMBC team reveals possibilities of new one-atom-thick materials
EurekAlert December 15, 2020 Researchers at the University of Maryland demonstrated theoretically and experimentally that properties of two-dimensional group-III nitride semiconductors can be controlled by alloying. They found that by changing the alloying concentration, the band gap and exciton binding energies of each structure can be tuned accordingly, and for certain concentrations, a high thermoelectric performance was reported with strong dependence on the effective mass of the given alloyed monolayer. In addition, they explained contribution of each electron–hole (e-h) pair by investigating the e–h coupling strength projected on the electronic band structure. They found that the exciton binding energy decreases […]
Molecules convert visible light into ultraviolet light with record efficiency
EurekAlert December 4, 2020 To directly convert visible light with wavelengths longer than 400 nm into higher-energy ultraviolet light researchers in Japan focused on triplet-triplet annihilation where triplets are formed on molecules following absorption of visible light. These “donor” molecules then give their triplets to “acceptor” molecules that can combine two triplets to create a single, higher-energy state that is released as ultraviolet light. They developed an acceptor molecule TIPS-naphthalene that has a high triplet-triplet-annihilation efficiency and a low enough triplet energy to easily accept triplets from a molecule called Ir(C6)2(acac). The combination of TIPS-naphthalene and Ir(C6)2(acac) successfully achieved the […]
Oddly satisfying metamaterials store energy in their skin
Science Daily December 2, 2020 Metamaterials’ properties are controlled through structural design at the mesoscale, thus broadening the design space beyond the limits of traditional materials. An international team of researchers (USA – Purdue University, Switzerland) experimented with a family of mechanical metamaterials consisting of soft sheets and patterned array of reconfigurable bistable domes. The domes can be reversibly inverted at the local scale to generate programmable multistable shapes and tunable mechanical responses at the global scale. By 3D printing a robotic gripper with energy‐storing skin and a structure that can memorize and compute spatially‐distributed mechanical signals, they have shown […]
Physicists Observe Trippy ‘Vortex Rings’ in a Magnetic Material For The First Time
Science Alert December 1, 2020 Magnetic ring vortices were predicted over 20 years ago in 1998. An international team of researchers (UK, Switzerland, Ukraine, Russia) have found vortex rings inside a tiny pillar made of the magnetic material gadolinium-cobalt intermetallic compound GdCo2. They developed an X-ray nanotomography technique to image the three-dimensional magnetization structure inside a GdCo2 bulk magnet. The vortices were paired with their topological counterparts, antivortices. They also found closed magnetic loops present in vortex-antivortex pairs. After computationally analysing these structures in the context of magnetic vorticity they figured out these were doughnut-shaped ring vortices, intersected by magnetization […]
Self-repairing gelatin-based film could be a smart move for electronics
Phys.org December 2, 2020 Self-repairing films have been developed, but most only work a single time, and some are made with potentially harmful agents that curtail their use in biomedical applications. Researchers in Taiwan mixed gelatin and glucose to create a flexible film that they sandwiched between conductive material to simulate an electronic device. After bending the simulated electronic device, the team saw breaks in the gelatin-glucose film disappear within three hours at room temperature and within 10 minutes when warmed to 140 F. Gelatin without glucose did not self-repair under the same conditions. The glucose-based gelatin also transferred an […]
Bioinspired metagel with broadband tunable impedance matching
Phys.org November 10, 2020 The concept of impedance matching has been established in electrical, acoustic, and optical engineering to maximize energy transmission from a source through a media. However, existing design of acoustic impedance matching, which extends exactly by a quarter wavelength, sets a fundamental limit of narrowband transmission. An international team of researchers (China, USA – MIT, Harvard University, Duke University, South Korea, Denmark, Canada, Scotland, Germany) has shown that a class of bioinspired metagel impedance transformers can overcome this limit. The transformer embeds a two-dimensional metamaterial matrix of steel cylinders into hydrogel. Using experimental data of the biosonar […]