A University of Miami physicist and his collaborators find remarkable thermoelectric properties for a metal that may impact the search for materials useful in power generation, refrigeration or energy detection
Thermoelectric materials can turn a temperature difference into an electric voltage. Among their uses in a variety of specialized applications: generating power on space probes and cooling seats in fancy cars.
Lithium purple-bronze (LiPB) is a thermoelectric material comprised of aligned conducting, zig-zag chains of molybdenum and oxygen (left image, pink and white circles with green bonds). When an electric current was applied in a direction slightly misaligned with the chains (depicted as gray lines, right image), heat flowed perpendicular to the current, a phenomenon known as the transverse Peltier effect. The efficiency of this effect in LiPB was among the largest known for a single compound.
Credit: Dr. Joshua Cohn, University of Miami
University of Miami (UM) physicist Joshua Cohn and his collaborators report new surprising properties of a metal named lithium purple-bronze (LiPB) that may impact the search for materials useful in power generation, refrigeration, or energy detection. The findings are published in the journal Physical Review Letters.
"If current efficiencies of thermoelectric materials were doubled, thermoelectric coolers might replace the conventional gas refrigerators in your home," said Cohn, professor and chairman of the UM Department of Physics in the College of Arts and Sciences and lead author of the study. "Converting waste heat into electric power, for example, using vehicle exhaust, is a near-term 'green' application of such materials."
Useful thermoelectric materials produce a large voltage for a given temperature difference, with the ratio known as "thermopower." LiPB is comprised of aligned conducting chains. The researchers found that this material has very different thermopowers when the temperature difference is applied parallel or perpendicular to the conducting chains.
When an electric current was applied in a direction slightly misaligned with the chains, heat flowed perpendicular to the current, a phenomenon known as the "transverse Peltier effect." The efficiency of this effect in LiPB was among the largest known for a single compound.
"That such a large directional difference in thermopower exists in a single compound is exceedingly rare and makes applications possible," Cohn said. "This is significant because transverse Peltier devices typically employ a sandwich of different compounds that is more complicated and costly to fabricate."
As their motivation for the work, Cohn noted that metals with a similar electronic structure often exhibit interesting physics and the thermoelectric properties of LiPB had never been studied in detail. "The present material," he said, "might be useful as it is, but the larger implication of our work is that the ingredients underlying its special properties may serve as a guide to finding or engineering new and improved materials."
The study is titled "Extreme Thermopower Anisotropy and Interchain Transport in the Quasi-One-Dimensional Metal Li0.9Mo6O17" Other authors of the study are Saeed Moshfeghyeganeh,Ph.D. student in the Department of Physics at UM; Carlos A. M. dos Santos, professor at the Escola de Engenharia de Lorena in Brazil and John J. Neumeier, professor in the Department of Physics, Montana State University.
Annette Gallagher | Eurek Alert!
Additive manufacturing reflects fundamental metallurgical principles to create materials
18.01.2019 | University of Sheffield
Brilliant glow of paint-on semiconductors comes from ornate quantum physics
17.01.2019 | Georgia Institute of Technology
The scientific and political community alike stress the importance of German Antarctic research
Joint Press Release from the BMBF and AWI
The Antarctic is a frigid continent south of the Antarctic Circle, where researchers are the only inhabitants. Despite the hostile conditions, here the Alfred...
World first experiments on sensor that may revolutionise everything from medical devices to unmanned vehicles
The new sensor - capable of detecting vibrations of living cells - may revolutionise everything from medical devices to unmanned vehicles.
Dead and alive at the same time? Researchers at the Max Planck Institute of Quantum Optics have implemented Erwin Schrödinger’s paradoxical gedanken experiment employing an entangled atom-light state.
In 1935 Erwin Schrödinger formulated a thought experiment designed to capture the paradoxical nature of quantum physics. The crucial element of this gedanken...
Cellulose obtained from wood has amazing material properties. Empa researchers are now equipping the biodegradable material with additional functionalities to produce implants for cartilage diseases using 3D printing.
It all starts with an ear. Empa researcher Michael Hausmann removes the object shaped like a human ear from the 3D printer and explains:
The phenomenon of so-called superlubricity is known, but so far the explanation at the atomic level has been missing: for example, how does extremely low friction occur in bearings? Researchers from the Fraunhofer Institutes IWM and IWS jointly deciphered a universal mechanism of superlubricity for certain diamond-like carbon layers in combination with organic lubricants. Based on this knowledge, it is now possible to formulate design rules for supra lubricating layer-lubricant combinations. The results are presented in an article in Nature Communications, volume 10.
One of the most important prerequisites for sustainable and environmentally friendly mobility is minimizing friction. Research and industry have been dedicated...
16.01.2019 | Event News
14.01.2019 | Event News
12.12.2018 | Event News
18.01.2019 | Materials Sciences
18.01.2019 | Life Sciences
18.01.2019 | Health and Medicine