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.)
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.
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.
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.
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.
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.
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.
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."
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.
It's a solid . . . it's a liquid . . . it's a LIQUID CRYSTAL! Researchers at the University of Wisconsin-Madison Materials Research Science and Engineering Center are investigating how the unique properties of liquid crystals allow them to act as environmental sensors, detecting toxins in the environment. In this video, we give a brief overview of what liquid crystals are and how their properties can be utilized to improve the world.
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.
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.
Recent progress in materials science has led to the creation of new magnetic materials in which the magnetism follows complex patterns. The formation of these patterns depends on a phenomenon called spin-orbital coupling. Because they can be manipulated by electric currents and temperature changes, materials exhibiting these interesting magnetic patterns may have applications in magnetic memories and logic devices.
One of the oldest and most studied materials in all of physics and materials science has been shown to display magnetism when illuminated with a certain type of light.
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."
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.
There are many ways atoms can arrange microscopically to form crystalline materials. Interestingly, materials created from different arrangements of the same atoms may exhibit completely different physical and chemical properties. A method called thin film epitaxy allows scientists not only to fine-tune the properties of known materials, but also to generate completely new materials with structures and properties not found in nature.
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.
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.
A bit of stray moisture during an experiment tipped off scientists about the strange behavior of a complex oxide material they were studying—shedding light on its potential for improving chemical sensors, computing and information storage. In the presence of a water molecule on its surface, the layered material emits ultraviolet light from its interior.
Transparent conducting oxides are unusual but highly useful materials that combine transparency to visible light, similar to glass, with high electrical conductivity, similar to copper and other metals.