Miller, SA;
Witting, I;
Aydemir, U;
Peng, L;
Rettie, AJE;
Gorai, P;
Chung, DY;
... Snyder, GJ; + view all
(2018)
Polycrystalline ZrTe5 Parametrized as a Narrow-Band-Gap Semiconductor for Thermoelectric Performance.
Physical Review Applied
, 9
(1)
, Article 014025. 10.1103/PhysRevApplied.9.014025.
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Abstract
The transition-metal pentatellurides HfTe 5 and ZrTe 5 have been studied for their exotic transport properties with much debate over the transport mechanism, band gap, and cause of the resistivity behavior, including a large low-temperature resistivity peak. Single crystals grown by the chemical-vapor-transport method have shown an n − p transition of the Seebeck coefficient at the same temperature as a peak in the resistivity. We show that behavior similar to that of single crystals can be observed in iodine-doped polycrystalline samples but that undoped polycrystalline samples exhibit drastically different properties: they are p type over the entire temperature range. Additionally, the thermal conductivity for polycrystalline samples is much lower, 1.5 Wm − 1 K − 1 , than previously reported for single crystals. It is found that the polycrystalline ZrTe 5 system can be modeled as a simple semiconductor with conduction and valence bands both contributing to transport, separated by a band gap of 20 meV. This model demonstrates to first order that a simple two-band model can explain the transition from n - to p -type behavior and the cause of the anomalous resistivity peak. Combined with the experimental data, the two-band model shows that carrier concentration variation is responsible for differences in behavior between samples. Using the two-band model, the thermoelectric performance at different doping levels is predicted, finding z T = 0.2 and 0.1 for p and n type, respectively, at 300 K, and z T = 0.23 and 0.32 for p and n type at 600 K. Given the reasonably high z T that is comparable in magnitude for both n and p type, a thermoelectric device with a single compound used for both legs is feasible.
| Type: | Article |
|---|---|
| Title: | Polycrystalline ZrTe5 Parametrized as a Narrow-Band-Gap Semiconductor for Thermoelectric Performance |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1103/PhysRevApplied.9.014025 |
| Publisher version: | https://doi.org/10.1103/PhysRevApplied.9.014025 |
| Language: | English |
| Additional information: | This version is the version of record. For information on re-use, please refer to the publisher’s terms and conditions. |
| Keywords: | Science & Technology, Physical Sciences, Physics, Applied, Physics, TRANSITION-METAL PENTATELLURIDES, THERMAL-CONDUCTIVITY, ELECTRONIC-STRUCTURE, DIMENSIONAL ZRTE5, PHASE-TRANSITION, HFTE5, RESISTIVITY, TRANSPORT, POWER, OSCILLATIONS |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Chemical Engineering |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10066561 |
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