Abnormally enhanced Hall Lorenz number in the magnetic Weyl semimetal NdAlSi

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Hauptverfasser: Zhang, Nan, Tu, Daifeng, Li, Ding, Tang, Kaixin, Nie, Linpeng, Li, Houpu, Li, Hongyu, Qi, Tao, Wu, Tao, Zhou, Jianhui, Xiang, Ziji, Chen, Xianhui
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Veröffentlicht: 2024
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author Zhang, Nan
Tu, Daifeng
Li, Ding
Tang, Kaixin
Nie, Linpeng
Li, Houpu
Li, Hongyu
Qi, Tao
Wu, Tao
Zhou, Jianhui
Xiang, Ziji
Chen, Xianhui
author_facet Zhang, Nan
Tu, Daifeng
Li, Ding
Tang, Kaixin
Nie, Linpeng
Li, Houpu
Li, Hongyu
Qi, Tao
Wu, Tao
Zhou, Jianhui
Xiang, Ziji
Chen, Xianhui
contents In Landau's celebrated Fermi liquid theory, electrons in a metal obey the Wiedemann--Franz law at the lowest temperatures. This law states that electron heat and charge transport are linked by a constant $L_0$, i.e., the Sommerfeld value of the Lorenz number ($L$). Such relation can be violated at elevated temperatures where the abundant inelastic scattering leads to a reduction of the Lorenz number ($L < L_0$). Here, we report a rare case of remarkably enhanced Lorenz number ($L > L_0$) discovered in the magnetic topological semimetal NdAlSi. Measurements of the transverse electrical and thermal transport coefficients reveal that the Hall Lorenz number $L_{xy}$ in NdAlSi starts to deviate from the canonical value far above its magnetic ordering temperature. Moreover, $L_{xy}$ displays strong nonmonotonic temperature and field dependence, reaching its maximum value close to 2$L_0$ in an intermediate parameter range. Further analysis excludes charge-neutral excitations as the origin of enhanced $L_{xy}$. Alternatively, we attribute it to the Kondo-type elastic scattering off localized 4$f$ electrons, which creates a peculiar energy distribution of the quasiparticle relaxation time. Our results provide insights into the perplexing transport phenomena caused by the interplay between charge and spin degrees of freedom.
format Preprint
id arxiv_https___arxiv_org_abs_2411_17156
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Abnormally enhanced Hall Lorenz number in the magnetic Weyl semimetal NdAlSi
Zhang, Nan
Tu, Daifeng
Li, Ding
Tang, Kaixin
Nie, Linpeng
Li, Houpu
Li, Hongyu
Qi, Tao
Wu, Tao
Zhou, Jianhui
Xiang, Ziji
Chen, Xianhui
Strongly Correlated Electrons
In Landau's celebrated Fermi liquid theory, electrons in a metal obey the Wiedemann--Franz law at the lowest temperatures. This law states that electron heat and charge transport are linked by a constant $L_0$, i.e., the Sommerfeld value of the Lorenz number ($L$). Such relation can be violated at elevated temperatures where the abundant inelastic scattering leads to a reduction of the Lorenz number ($L < L_0$). Here, we report a rare case of remarkably enhanced Lorenz number ($L > L_0$) discovered in the magnetic topological semimetal NdAlSi. Measurements of the transverse electrical and thermal transport coefficients reveal that the Hall Lorenz number $L_{xy}$ in NdAlSi starts to deviate from the canonical value far above its magnetic ordering temperature. Moreover, $L_{xy}$ displays strong nonmonotonic temperature and field dependence, reaching its maximum value close to 2$L_0$ in an intermediate parameter range. Further analysis excludes charge-neutral excitations as the origin of enhanced $L_{xy}$. Alternatively, we attribute it to the Kondo-type elastic scattering off localized 4$f$ electrons, which creates a peculiar energy distribution of the quasiparticle relaxation time. Our results provide insights into the perplexing transport phenomena caused by the interplay between charge and spin degrees of freedom.
title Abnormally enhanced Hall Lorenz number in the magnetic Weyl semimetal NdAlSi
topic Strongly Correlated Electrons
url https://arxiv.org/abs/2411.17156