Enhanced thermopower in a magnetic semiconductor EuTe4 with multiple charge-density-wave instabilities/

Fuente: arXiv
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Main Authors: Takahashi, Hidefumi, Yoshida, Kiichiro, Nakano, Akitoshi, Ishiwata, Shintaro
Format: Preprint
Published: 2025
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_version_ 1866918128912433152
author Takahashi, Hidefumi
Yoshida, Kiichiro
Nakano, Akitoshi
Ishiwata, Shintaro
author_facet Takahashi, Hidefumi
Yoshida, Kiichiro
Nakano, Akitoshi
Ishiwata, Shintaro
contents We investigate the layered magnetic semiconductor EuTe4, focusing on its intricate charge-density wave (CDW) states near and above room temperature through single-crystal X-ray diffraction (XRD), magnetic, and thermoelectric measurements.The XRD measurement revealed that the CDW state inducing the polar lattice distortion persists even at 650 K, demonstrating its remarkable thermal stability. Notably, the Seebeck coefficient near room temperature reaches values exceeding 500 uVK-1. This large Seebeck coefficient, not fully captured by a simple band calculation, is comparable to those observed in heavy-electron semiconducting oxides, suggesting the importance of electron correlation and spin/lattice instabilities. Furthermore, potentially reflecting the competition of two types of CDW states, the thermal conductivity near room temperature is as low as 0.02 Wcm-1K-1. As a result, the thermoelectric figure of merit zT reaches 0.22 at 460 K. These findings establish EuTe4 as a compelling platform to explore novel types of thermoelectric materials with multiple electronic instability.
format Preprint
id arxiv_https___arxiv_org_abs_2508_16017
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Enhanced thermopower in a magnetic semiconductor EuTe4 with multiple charge-density-wave instabilities/
Takahashi, Hidefumi
Yoshida, Kiichiro
Nakano, Akitoshi
Ishiwata, Shintaro
Materials Science
Strongly Correlated Electrons
We investigate the layered magnetic semiconductor EuTe4, focusing on its intricate charge-density wave (CDW) states near and above room temperature through single-crystal X-ray diffraction (XRD), magnetic, and thermoelectric measurements.The XRD measurement revealed that the CDW state inducing the polar lattice distortion persists even at 650 K, demonstrating its remarkable thermal stability. Notably, the Seebeck coefficient near room temperature reaches values exceeding 500 uVK-1. This large Seebeck coefficient, not fully captured by a simple band calculation, is comparable to those observed in heavy-electron semiconducting oxides, suggesting the importance of electron correlation and spin/lattice instabilities. Furthermore, potentially reflecting the competition of two types of CDW states, the thermal conductivity near room temperature is as low as 0.02 Wcm-1K-1. As a result, the thermoelectric figure of merit zT reaches 0.22 at 460 K. These findings establish EuTe4 as a compelling platform to explore novel types of thermoelectric materials with multiple electronic instability.
title Enhanced thermopower in a magnetic semiconductor EuTe4 with multiple charge-density-wave instabilities/
topic Materials Science
Strongly Correlated Electrons
url https://arxiv.org/abs/2508.16017