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Category: materials – Page 294

For the first time, MIT physicists have observed a highly ordered crystal of electrons in a semiconducting material and documented its melting, much like ice thawing into water. The observations confirm a fundamental phase transition in quantum mechanics that was theoretically proposed more than 80 years ago but not experimentally documented until now.

The team, led by MIT professor of physics Raymond Ashoori and his postdoc Joonho Jang, used a spectroscopy technique developed in Ashoori’s group. The method relies on electron “tunneling,” a quantum mechanical process that allows researchers to inject electrons at precise energies into a system of interest—in this case, a system of electrons trapped in two dimensions. The method uses hundreds of thousands of short electrical pulses to probe a sheet of electrons in a cooled to extremely low temperatures, just above absolute zero.

With their tunneling technique, the researchers shot electrons into the supercooled material to measure the energy states of electrons within the semiconducting sheet. Against a background blur, they detected a sharp spike in the data. After much analysis, they determined that the spike was the precise signal that would be given off from a highly ordered crystal of electrons vibrating in unison.

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At the forefront of computing technology for decades, silicon-based chips’ reign may soon end, as today’s chip designers are looking for other materials that offer more options and more amazing abilities than the silicon we all know and love.

This new trend has spurred the guys at Oak Ridge National Laboratory (ORNL) to develop what could be the foundation for multi-role computer chips.

In a recent study, ORNL scientists looked at single crystal complex oxide materials at the very smallest levels. They discovered that that contained in just one piece of this material were multiple tiny regions that each responded to magnetic and electrical stimuli differently.

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With the help of this material, scientists are a little bit closer to unlocking the mystery of how the rules of the quantum realm translate to the rules of the classical physics of the observable world.

Experts predict that the materials used in this research, topological insulators, will play a key role in furthering this development.

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Nice write on polymeric coatings as a material option consider when developing implants replicating a natural electrode charge without creating damage or disruptions. Author proposes such materials could be leveraged beyond their use today and expanded to include BMI implants. Definitely, will take a closer look at.

Jeff Hendricks Biotectix outlines how polymeric coatings can help improve the performance of medical and consumer electronic devices.

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For all my Lab friends who utilize Spectrometers, drill bit fans as well as many of us QC fans. A new stronger syn. diamond being developed.

But you won’t find this diamond on any engagement rings — it will help cut through ultra-solid materials on mining sites.

Step aside, girls. Diamonds may now be a miner’s best friend, thanks to scientists from Australian National University (ANU).

Led by ANU professor Jodie Bradby, an international team is creating a hexagonal diamond, called Lonsdaleite, that’s predicted to be harder than a jeweler’s diamond. The researchers made nano-sized Lonsdaleite at 400 degrees Celsius (752 degrees Fahrenheit), effectively halving the temperature in which it can be formed in a lab. They’ve published their work in Scientific Reports.

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Thermoelectric generators convert heat or cold to electricity (and vice-versa). Normally solid-state devices, they can be used in such things as power plants to convert waste heat into additional electrical power, or in small cooling systems that do not need compressors or liquid coolant. However the rigid construction of these devices generally limits their use to flat, even surfaces. In an effort to apply thermal generation capabilities to almost any shape, scientists at the Ulsan National Institute of Science and Technology (UNIST) in Korea claim to have created a thermoelectric coating that can be directly painted onto most surfaces.

Variously known as the Peltier, Seebeck, or Thomson effect, the thermoelectric effect is seen in semiconductor devices that create a voltage when a different temperature is present on each side or, when a voltage is applied to the device, it creates a temperature difference between the two sides. In this instance, the new paint created by the UNIST researchers is used specifically to heat a surface when a voltage is applied.

The specially-formulated inorganic thermoelectric paint was created using Bi2Te3 (bismuth telluride) and Sb2Te3 (antimony telluride) particles to create two types of semiconducting material. To test the resultant mixture, the researchers applied alternate p-type (positive) and n-type (negative) layers of the thermoelectric semiconductor paint on a metal dome with electrodes at the top and the base of the dome.

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Researchers from Brown University have demonstrated an unusual method of putting the brakes on superconductivity, the ability of a material to conduct an electrical current with zero resistance.

The research shows that weak magnetic fields—far weaker than those that normally interrupt superconductivity—can interact with defects in a material to create a “random gauge field,” a kind of quantum obstacle course that generates resistance for superconducting electrons.

“We’re disrupting superconductivity in a way that people haven’t done before,” said Jim Valles, a professor of physics at Brown who directed the work. “This kind of phase transition involving a random gauge field had been predicted theoretically, but this is the first time it has been demonstrated in an experiment.”

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