Abstract
We theoretically study the thermoelectric properties of electron-doped FeAs2 and hole-doped PtSe2 from a band-structure point of view using first-principles band calculations. The band structure of both materials has a peculiar band shape with a flat portion at the top (bottom) of the band, namely the pudding-mold-type band as found in Na x CoO 2. The pudding-mold-type band has a quasi-one-dimensional nature in FeAs2 and a quasi-two-dimensional nature in PtSe2. We study the origins of the pudding-mold-type band and find that the dz2 orbital in FeAs2, and not only the p z but also the p x and the p y orbitals in PtSe2 play an important role in making the pudding-mold-type band. We calculate the Seebeck coefficients by the Boltzmann equation approach using a tight-binding model constructed from first-principles band calculations, finding values close to experimental observations. The present study shows the general efficiency of the pudding-mold-type band. We suggest that an efficient route towards obtaining good thermoelectric materials is to realize ideal pudding-mold-type bands by modification of lattice structures.
Original language | English |
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Pages (from-to) | 1656-1661 |
Number of pages | 6 |
Journal | Journal of Electronic Materials |
Volume | 43 |
Issue number | 6 |
DOIs | |
Publication status | Published - 2014 |
Keywords
- Thermoelectric effect
- band structure
- first-principles calculation
- structure dependence
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering
- Materials Chemistry