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Recent research has revealed that thermoelectric crystals can show higher conductivity. A temperature difference can generate a current flow in thermoelectric materials governed by its “Peltier conductivity” (P) Researchers from Japan demonstrate an unprecedented large P in a single crystal of Ta2PdSe6 that is 200 times larger than the maximum P commercially available. This could open doors to new research avenues and revolutionize modern electronics, they say.
The phenomenon called the “Seebeck effect” laid the foundation of the field of thermoelectrics, which deals with materials producing electricity under the application of temperature difference.
A P of 100 A cm-1 K-1 at a temperature of 10 K in a Ta2PdSe6 crystal is the largest ever reported for bulk solid. A large P could be a game-changer for modern-day electronics. The Peltier conductivity of thermoelectricity is governed by electrical conductivity, P, which relates the current to the temperature gradient. A new study published in the Journal of Physics: Energy has raised hopes on this front.
Ta2PdSe6 showed rapid growth in P below 100 K, reaching a value higher by two orders of magnitude. This suggested that the large P stemmed from a low residual resistivity. The team prepared high-quality single crystals of Ta2pdSe 6 and characterized its chemical composition using scanning electron microscopy.
They measured its electrical conductivity, thermopower, and Hall resistivity and performed calculations based on a two-carrier model considering electrons and holes to explain their findings.
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Ta2PdSe6 could be used as a current source for a superconducting solenoid isolated in a cryogenic space. A cubic sample of 1 cc could supply a current of 100 A to the solanoid for a temperature difference of 1 K. The absence of external current leads would make the system compact and concise, reducing cooling costs. This could be then carried over to the design of a compact, low-cost MRI machine, making medical diagnosis more convenient in the future.
Further information
Akitoshi Nakano et al, Giant Peltier conductivity in an uncompensated semimetal Ta2PdSe6, Journal of Physics: Energy (2021). DOI: 10.1088/2515-7655/ac2357