Enhancement of thermoelectric performance via weak disordering of topological crystalline insulators and band convergence by Se alloying in Pb0.5Sn0.5Te1 − xSex
| Autor: | Jong-Soo Rhyee, Byung Kyu Yu, Gareoung Kim, Kyunghan Ahn, Sung Jin Kim, Jae Hyun Yun, Chan Chieh Lin, Dianta Ginting |
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| Rok vydání: | 2018 |
| Předmět: |
Materials science
Extended X-ray absorption fine structure Renewable Energy Sustainability and the Environment Doping 02 engineering and technology General Chemistry 010402 general chemistry 021001 nanoscience & nanotechnology Thermoelectric materials Topology 01 natural sciences Semimetal 0104 chemical sciences Crystal Condensed Matter::Materials Science Condensed Matter::Superconductivity Seebeck coefficient Thermoelectric effect Topological order Condensed Matter::Strongly Correlated Electrons General Materials Science 0210 nano-technology |
| Zdroj: | Journal of Materials Chemistry A. 6:5870-5879 |
| ISSN: | 2050-7496 2050-7488 |
| DOI: | 10.1039/c8ta00381e |
| Popis: | Topological crystal insulators (TCIs) that have an even number of topologically protected Dirac bands driven by crystalline mirror symmetry have attracted much attention in condensed matter physics. Here, we demonstrate that a weak disordering in the topological crystalline state can enhance thermoelectric performance significantly due to highly dispersive band dispersion and high band degeneracy which guarantee high electrical mobility and a high Seebeck coefficient, respectively. When we perturb a crystalline mirror symmetry by Se-doping in TCI Pb0.5Sn0.5Te1 − xSex, the topological state becomes weak so that it eventually evolves the normal state. We experimentally prove the topological phase transition concerning Se concentration by X-ray Absorption Spectroscopy (XAS) and extended X-ray absorption Fine Structure (EXAFS) analysis. Small crystalline perturbation by Se doping (x = 0.05) significantly enhances thermoelectric performance due to the simultaneous enhancement of electrical conductivity and the Seebeck coefficient. Therefore, we report an exceptionally high ZT value of 1.9 at 800 K for the x = 0.05 compound which is a 313% enhancement of ZT compared with the pristine compound. This research proposes a new strategy for exploring high-performance thermoelectric materials by weak disordering of topological crystalline Dirac semimetals. |
| Databáze: | OpenAIRE |
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