Pressure-induced phase transition and electrical properties of thermoelectric Al-doped Mg2Si
- Univ. of Saskatchewan, Saskatoon, SK (Canada)
- Carnegie Inst. of Washington, Washington, DC (United States)
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Okayama Univ. of Science, Okayama (Japan)
- Canadian Light Source, Inc., Saskatoon, SK (Canada)
A recent study has shown the thermoelectric performance of Al-doped Mg2Si materials can be significantly enhanced at moderate pressure. To understand the cause of this phenomenon, we have performed in situ angle dispersive X-ray diffraction and infrared reflectivity measurements up to 17 GPa at room temperature. Contrary to previous experiment, using helium as a pressure transmission medium, no structural transformation was observed in pure Mg2Si. In contrast, a phase transition from cubic anti-fluorite (Fm-3m) to orthorhombic anti-cotunnite (Pnma) was observed in the Al-doped sample at 10 GPa. Infrared reflectivity measurements show the electrical conductivity increases with pressure and is further enhanced after the phase transition. The electron density of states at the Fermi level computed form density functional calculations predict a maximum thermoelectric power factor at 1.9 GPa, which is in good agreement with the experimental observation.
- Research Organization:
- Argonne National Laboratory (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities Division
- Grant/Contract Number:
- AC02-06CH11357; FC03 03N00144; AC02-98CH10886
- OSTI ID:
- 1224008
- Alternate ID(s):
- OSTI ID: 1420463
- Journal Information:
- Journal of Applied Physics, Vol. 118, Issue 14; ISSN 0021-8979
- Publisher:
- American Institute of Physics (AIP)Copyright Statement
- Country of Publication:
- United States
- Language:
- ENGLISH
Web of Science
High pressure synthesis of multiple doped Mg2Si-based thermoelectric materials
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journal | April 2018 |
Strategies and challenges of high-pressure methods applied to thermoelectric materials
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journal | June 2019 |
High-pressure phases of from first principles
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journal | March 2016 |
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