Zhao, T;
Daniels, LM;
Ben, S;
Rosseinsky, MJ;
Cora, F;
(2020)
Effects of Octahedral Tilting on Band Structure and Thermoelectric Power Factor of Titanate Perovskites: A First-Principles Study on SrTiO₃.
Journal of Physical Chemistry C
, 124
(24)
pp. 13045-13052.
10.1021/acs.jpcc.0c03513.
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Abstract
Doped SrTiO_{3} and other perovskite structured titanates are attracting interest as n-type thermoelectric materials due to their relatively high thermoelectric power factor, low toxicity, and modest cost. Taking SrTiO_{3} as an example, the effects of octahedral tilting on the electronic band structure and thermoelectric power factor of titanate perovskites have been studied from first-principles calculations. By utilizing Glazer’s notation, six representative tilt systems, including three out-of-phase (a^{0}a^{0}c^{–}, a^{0}b^{-}b^{–}, and a^{–}a^{–}a^{–}) and three in-phase tilt systems (a^{0}a^{0}c^{+}, a^{0}b^{+}b^{+}, and a^{+}a^{+}a^{+}), were investigated. It is found that out-of-phase tilting improves the optimum power factor as compared to the cubic aristotype, while in-phase tilting marginally lowers the optimum power factor. The largest increase in power factor (∼100%) is obtained in the one-tilt system a^{0}a^{0}c^{–} at a tilt angle of 15°, which can be achieved with an energy cost of only 44 kJ mol^{–1} per formula unit. These findings agree with the experimental evidence that increased power factors are found in a^{0}a^{0}c^{–} and a^{–}a^{–}a^{–} tilt systems of titanate perovskites. The predicted increase of Seebeck coefficient as a function of tilt angle in the a^{–}a^{–}a^{–} tilt system of SrTiO_{3} is also consistent with the experimental increase of Seebeck coefficient in a^{–}a^{–}a^{–} titanates of La_{0.55}K_{0.45}TiO_{3} and La_{0.5}Na_{0.5}Ti_{0.9}Nb_{0.1}O_{3}. Our simulations provide valuable insights into tuning the thermoelectric power factor of titanate perovskites by controlling octahedral tilting.
| Type: | Article |
|---|---|
| Title: | Effects of Octahedral Tilting on Band Structure and Thermoelectric Power Factor of Titanate Perovskites: A First-Principles Study on SrTiO₃ |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1021/acs.jpcc.0c03513 |
| Publisher version: | https://doi.org/10.1021/acs.jpcc.0c03513 |
| Language: | English |
| Additional information: | This version is the author accepted manuscript. For information on re-use, please refer to the publisher's terms and conditions. |
| Keywords: | Thermoelectrics, Oxides, Anions, Power, Perovskites |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Chemistry |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10107383 |
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