Charge carrier effective mass and concentration derived from combination of Seebeck coefficient and NMR measurements in complex tellurides
Journal Article
·
· Physical Review B
- Ames Lab. and Iowa State Univ., Ames, IA (United States)
Thermoelectric materials utilize the Seebeck effect to convert heat to electrical energy. The Seebeck coefficient (thermopower), S, depends on the free (mobile) carrier concentration, n, and effective mass, m*, as S ~ m*/n2/3. The carrier concentration in tellurides can be derived from 125Te nuclear magnetic resonance (NMR) spin-lattice relaxation measurements. The NMR spin-lattice relaxation rate, 1/T1, depends on both n and m* as 1/T1~(m*)3/2n (within classical Maxwell-Boltzmann statistics) or as 1/T1~(m*)2n2/3 (within quantum Fermi-Dirac statistics), which challenges the correct determination of the carrier concentration in some materials by NMR. Here it is shown that the combination of the Seebeck coefficient and 125Te NMR spin-lattice relaxation measurements in complex tellurides provides a unique opportunity to derive the carrier effective mass and then to calculate the carrier concentration. This approach was used to study AgxSbxGe50–2xTe50, well-known GeTe-based high-efficiency tellurium-antimony-germanium-silver thermoelectric materials, where the replacement of Ge by [Ag+Sb] results in significant enhancement of the Seebeck coefficient. Thus, values of both m* and n derived using this combination show that the enhancement of thermopower can be attributed primarily to an increase of the carrier effective mass and partially to a decrease of the carrier concentration when the [Ag+Sb] content increases.
- Research Organization:
- Ames Laboratory (AMES), Ames, IA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES); USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
- Grant/Contract Number:
- AC02-07CH11358
- OSTI ID:
- 1278781
- Alternate ID(s):
- OSTI ID: 1259584
- Report Number(s):
- IS-J--9009
- Journal Information:
- Physical Review B, Journal Name: Physical Review B Journal Issue: 24 Vol. 93; ISSN 2469-9950; ISSN PRBMDO
- Publisher:
- American Physical Society (APS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
Thermodynamic and thermoelectric properties of CoFeYGe (Y = Ti, Cr) quaternary Heusler alloys: first principle calculations
|
journal | November 2019 |
Similar Records
Electronic inhomogeneity and Ag:Sb imbalance of Ag1-yPb18/207Sb1+zTe20 high-performance thermoelectrics elucidated by 125Te and 207Pb NMR
Electronic properties of GeTe and Ag- or Sb-substituted GeTe studied by low-temperature NMR
125Te NMR and Seebeck Effect in Bi2Te3 Synthesized from Stoichiometric and Te-Rich Melts
Journal Article
·
Tue Sep 22 00:00:00 EDT 2009
· Physical Review B
·
OSTI ID:967139
Electronic properties of GeTe and Ag- or Sb-substituted GeTe studied by low-temperature NMR
Journal Article
·
Wed Aug 17 20:00:00 EDT 2016
· Physical Review B
·
OSTI ID:1326845
125Te NMR and Seebeck Effect in Bi2Te3 Synthesized from Stoichiometric and Te-Rich Melts
Journal Article
·
Thu Oct 13 20:00:00 EDT 2016
· Journal of Physical Chemistry. C
·
OSTI ID:1342943