Back to Search
Start Over
Paramagnon drag in high thermoelectric figure of merit Li-doped MnTe
- Source :
- Science Advances
- Publication Year :
- 2018
-
Abstract
- Neutrons spot magnetic fluctuations that propel charges in a novel class of paramagnetic thermoelectrics.<br />Local thermal magnetization fluctuations in Li-doped MnTe are found to increase its thermopower α strongly at temperatures up to 900 K. Below the Néel temperature (TN ~ 307 K), MnTe is antiferromagnetic, and magnon drag contributes αmd to the thermopower, which scales as ~T3. Magnon drag persists into the paramagnetic state up to >3 × TN because of long-lived, short-range antiferromagnet-like fluctuations (paramagnons) shown by neutron spectroscopy to exist in the paramagnetic state. The paramagnon lifetime is longer than the charge carrier–magnon interaction time; its spin-spin spatial correlation length is larger than the free-carrier effective Bohr radius and de Broglie wavelength. Thus, to itinerant carriers, paramagnons look like magnons and give a paramagnon-drag thermopower. This contribution results in an optimally doped material having a thermoelectric figure of merit ZT > 1 at T > ~900 K, the first material with a technologically meaningful thermoelectric energy conversion efficiency from a spin-caloritronic effect.
- Subjects :
- 02 engineering and technology
7. Clean energy
01 natural sciences
Quantitative Biology::Cell Behavior
Magnetization
Paramagnetism
Condensed Matter::Materials Science
Seebeck coefficient
Condensed Matter::Superconductivity
0103 physical sciences
Antiferromagnetism
Research Articles
010302 applied physics
Physics
Physics::Biological Physics
Multidisciplinary
Condensed matter physics
Magnon
SciAdv r-articles
021001 nanoscience & nanotechnology
Condensed Matter::Strongly Correlated Electrons
Matter wave
0210 nano-technology
Néel temperature
Bohr radius
Research Article
Subjects
Details
- ISSN :
- 23752548
- Volume :
- 5
- Issue :
- 9
- Database :
- OpenAIRE
- Journal :
- Science advances
- Accession number :
- edsair.doi.dedup.....b465e6480b795a8112df082678ef0f17