Posts showcasing the wonder, beauty, and potential of cutting-edge materials research—freely contributed by physicists from across the country. (Funsize Physics is not responsible for any minds that are blown.)
Superconductors are materials that permit electrical current to flow without energy loss. Their amazing properties form the basis for MRI (magnetic resonance imaging) devices and high-speed maglev trains, as well as emerging technologies such as quantum computers. At the heart of all superconductors is the bunching of electrons into pairs. Click the image to learn more about the "dancing" behavior of these electron pairs!
You may know helium as the gas that can make balloons and blimps float. At the University of Maryland, scientists are using this element to study the exotic physics of quantum vortices: the tornadoes or bathtub-drain whirls of the quantum world. Knowing how quantum vortices work could help us better understand other turbulent events (like wind and ocean currents), as well as the complex physical behavior of superconductors and neutron stars.
Scientists are working to develop electronic devices that store and process information by manipulating a property of electrons called spin—a research area aptly known as spintronics. The semiconductors we are developing will not only be faster and cheaper than those used in conventional devices, but will also have more functionality.
The electric eel's ability to generate incredibly large amounts of electric power from within its body has fascinated scientists for centuries. In fact, some of the world’s first batteries were inspired by studies of this amazing animal. Now, scientists have developed a new eel-inspired energy source that may one day be used to power electronics implanted within the human body.
Diodes, also known as rectifiers, are a basic component of modern electronics. As we work to create smaller, more powerful and more energy-efficient electronic devices, reducing the size of diodes is a major objective. Recently, a research team from the University of Georgia developed the world's smallest diode using a single DNA molecule. This diode is so small that it cannot be seen by conventional microscopes.
Carbon-based nanostructures are among the most intensely studied systems in nanotechnology. Potential practical applications span the fields of medicine, consumer electronics, and hydrogen storage, and they could even be used to develop a space elevator. A research team at the University of Northern Iowa is probing the properties of multilayered carbon nanostructures known as "carbon onions."
Semiconductors are materials with properties intermediate between metals and non-conducting insulators, defined by the amount of energy needed to make an electron conductive in the material. The non-conducting electrons occupy a continuum of energy states, but two of these states (the “heavy hole” and “light hole”) are nearly identical in energy. The heavy hole is easy to observe and study, but the light hole eludes most observers.
Very small structures, much smaller than the human eye can see, often fall in the size range of nanometers. By understanding how the molecules that make up these structures interact, we can engineer them to do many special things that cannot be done at a larger scale. One exciting structure is a polymer brush, in which long, chain-like molecules called polymers are tethered at one end to a surface and stick up from the surface like bristles on a hairbrush. Polymer brushes can be used to keep bacteria away, provide an exceptionally smooth surface for items to slide across, or trap other molecules in solution like a hairbrush traps loose hair. In order to engineer polymer brushes that will perform as desired for a given application, we must understand the physics of how the molecular bristles move, and the chemistry of how they interact with their environment.
Many solid materials have a crystal structure, with atoms that exist in a particular, organized arrangement. The degree of organization can vary among crystals, however. High-quality crystalline materials are the foundation of many familiar devices, such as integrated circuits and solar cells. A better understanding of these materials and how to produce them is important for developing new technologies.
At ordinary temperatures and at the subatomic level, chaos is the rule. At low enough temperatures, however, electrons are constrained, forming exotic phases that exhibit long-range order, or repeating patterns.
How can you fabricate a huge number of nanostructures in a split second? Self-assembly is a fast technique for the mass production of materials and complex structures. But before self-assembly is ready for prime time, scientists need to establish ways to control this process, so that desired nanostructures emerge from the unstructured soup of basic building blocks that are fast-moving atoms and molecules.
Essentially all of our technology is built by manipulating materials on length scales between a tenth of a billionth of a meter (atom-sized) and a thousand meters (skyscraper-sized). We call this range of sizes "funsize."
Biophysics is a field that applies knowledge of physics to understand and explain biological phenomena. Biophysicists study life at different levels, from atoms and molecules to cells, organisms, and their environments. They focus on questions such as how proteins function, how nerve cells communicate, how viruses invade human cells, how plants absorb sunlight and convert it into food, and so on. Biophysics has contributed significantly to improving human health in multiple ways, and the study of protein-protein interactions is an especially important biophysical topic. By exploring the molecular basis of complicated biomedical diseases, biophysicists help to develop methods to treat these diseases.
Superconductors and magnetic fields do not usually get along, but a research team led by a Brown University physicist has produced new evidence for an exotic superconducting state that can indeed arise when a superconductor is subject to a strong magnetic field. Their results could enable scientists to develop materials for more efficient memory storage, and even help to explain the behavior of distant astronomical objects called pulsars.
Inside solids, the properties of photons can be altered in ways that create a kind of "artificial gravity" that affects light. Researchers at the University of Pittsburgh tracked photons with a streak camera and found that whey they enter a solid-state structure, they act just like a ball being thrown in the air: they slow down as they move up, come to a momentary stop, and fall back the other way. Studying this "slow reflection" will allow us to manipulate light's behavior, including its speed and direction, with potential applications in telecommunications and quantum computing technologies.
Materials that are absolutely perfect—in other words, materials that contain no defect of any kind—are usually not very interesting. Imagine being married to a saint: you would quickly be bored out of your mind! Defects and impurities can considerably change many properties of materials in ways that allow a wide range of applications.
Scientists and engineers are making smaller and smaller structures designed to control the quantum states of electrons in a material. By controlling quantum mechanics, we can create new materials that do not exist in nature, develop more efficient solar cells and faster computer chips, and even discover exotic new states of matter.
Solids are generally divided into metals, which conduct electricity, and insulators, which do not. Some oxides straddle this boundary, however: a material's structure and properties suggest it should be a metal, but it sometimes behaves as an insulator. Researchers at the University of California, Santa Barbara are digging into the mechanisms of this transformation and are aiming to harness it for use in novel electronic devices.
In a unique state of matter called a superfluid, tiny "tornadoes" form that may play an important role in nanotechnology, superconductivity, and other applications. Just as tornadoes are invisible air currents that become visible when they suck debris into their cores, the quantum vortices in superfluids attract atoms that make the vortices visible. Quantum vortices are so small they can only be imaged using very short-wavelength x-rays, however.
You may know that the media used in magnetic recording technologies, such as computer hard drives, are made of millions of tiny nanomagnets. Each nanomagnet can be switched up or down to record bits of information as ones and zeros. These media are constantly subjected to magnetic fields in order to write, read, and erase information. If you have ever placed a magnet too close to your laptop or cell phone, you know that exposure to an external magnetic field can disrupt information stored this way. Did you know that it is possible for the nanomagnets to "remember" their previous state, if carefully manipulated under specific magnetic field and temperature conditions? Using a kind of memory called topological magnetic memory, scientists have found out how to imprint memory into magnetic thin films by cooling the material under the right conditions.