CEM Research Advances Thermoelectrics as Waste Heat Recovery Technology

Sometimes instead of generating waste, heat can be utilized to generate power and increase energy efficiency. Newly published research by CEM Profs. McComb and Heremans explain how in this week’s Nature CommunicationsAccording to CEM Postdoc, Dr. Stephen Boona:

“Over half of the energy we use is wasted and enters the atmosphere as heat. Solid-state thermoelectrics can help us recover some of that energy we’re already producing but not using. These devices have no moving parts, don’t wear out, are robust and require no maintenance. Unfortunately, to date, they are also not quite efficient enough to warrant widespread use. We’re working to change that.”

Read more here.

Researchers Discover New Electronic Phase of Matter: Topological Weyl Semimetal

IRG-1 Researchers Professor Nandini Trivedi and her graduate student Tim McCormick, in collaboration with Professor Adam Kaminski (Iowa State University) and Dr. Jiaqiang Yan (ORNL) and their students, discovered a new electronic phase of matter known as a topological Weyl semimetal.  This novel quantum phase hosts excitations known as Weyl fermions, first predicted in high energy physics in 1929 but only recently experimentally discovered in quantum materials.  Using theoretical modeling and angle-resolved photoemission spectroscopy, the team identified the first type-II Weyl semimetal phase in the layered transition metal compound MoTe2.  Type-II Weyl fermions break Lorentz invariance, a symmetry obeyed by all fundamental particles, so Weyl semimetals hosting these excitations allow for the testing of exotic physics beyond the standard model in a tabletop experiment.  They possess electron and hole pockets that touch at topologically protected points in momentum space and form Fermi arcs and newly predicted track states on the surface that result in unique magneto-transport properties of these materials.  Additionally, the Weyl excitations are robust against external perturbations, providing a resilient platform for possible information storage as well as opening the door for electronic applications. Read the new publication in Nature Materials.

CEM Faculty Jos Heremans Featured in Nature ‘News and Views’ Article: “Thermoelectricity: The ugly duckling”

With tin sometimes described as one of the base (think homeliest) metals, perhaps it should come as no surprise that it, like the misidentified cygnet in Hans Christian Andersen’s tale The Ugly Duckling, may actually be inherently beautiful — at least in the eyes of those who appreciate the potential of thermoelectricity.

To draw the analogy, Professor Joseph Heremans, borrowed the title “Thermoelectricity: The ugly duckling” for an article that he authored and which appears in the April 17, 2014 print edition (Volume 508) of the journal Nature. The article, which can be found on pages 327-328 in the News and Views section of the journal, details why there’s beauty (or higher than imagined thermoelectric efficiency) in the single crystals of tin selenide. The article also serves as context for a research paper authored by a group Northwestern University researchers whom belong to the same Energy Frontier Research Center as Professor Heremans and his research team. 

According to Heremans, the study led by Professor Mercouri Kanatzidis at Northwestern University, his graduate student Li-Dong Zhao and colleagues further underscores the fact that progress in the thermal sciences relative to thermoelectric power applications has been unrelenting and discoveries about thermal conductivity often quite surprising.

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Recent CEM results published in Nature Nanotechnology – Could diamonds be a computer’s best friend?

Recent CEM results published in Nature Nanotechnology

Could diamonds be a computer’s best friend?

March 24, 2014

For the first time, CEM researchers have demonstrated that information can flow through a diamond wire. In the experiment, electrons did not flow through diamond as they do in traditional electronics; rather, they stayed in place and passed along a magnetic effect called “spin” to each other down the wire—like a row of sports spectators doing “the wave.

Spin could one day be used to transmit data in computer circuits—and this new experiment, done at The Ohio State University, revealed that diamond transmits spin better than most metals in which researchers have previously observed the effect.

Further information on this research can be found in this article and in the publication.