Abstract
The quality factor B involving carrier mobility, state density effective mass, and lattice thermal conductivity has always been regarded as the guidance for the thermoelectric materials design. However, the traditional quality factor considers a single band and neglects the influence of band gap and the sub-band, whose edge energy is 5 kBT lower than valence band maximum for the p-type or higher than conduction band minimum for n-type semiconductor. In this work, we took into account the band gap and second band based on the three-parabolic-band model and derived an advanced quality factor BΔE∗, which is better proportional to the peak ZT values of many compounds with multiple bands. A specific example is also validated based on this quality factor that a highest BΔE∗ appears when x = 0.8 for (Yb0.9Mg0.1)MgxZn2-xSb2, leading to the highest ZT value at this composition.
Original language | English |
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Article number | 100371 |
Journal | Materials Today Physics |
Volume | 18 |
DOIs | |
State | Published - May 2021 |
Externally published | Yes |
Keywords
- Band offset
- Multiple bands
- Quality factor
- Thermoelectric materials