Wang Yi-Yan, Rao Xin, Zhou Ying, Zhu Xiang-De, Zhao Xia, Chen Gang, Li Na, Liang Hui, Xia Tian-Long, Sun Xue-Feng
Anhui Key Laboratory of Magnetic Functional Materials and Devices, Institutes of Physical Science and Information Technology, Anhui University, Hefei, Anhui, China.
School of Physical Sciences, University of Science and Technology of China, Hefei, Anhui, China.
Nat Commun. 2025 Jan 2;16(1):53. doi: 10.1038/s41467-024-55141-w.
Thermal conductivity and electrical resistivity at ultralow temperatures and high magnetic fields are studied in the topological compensated semimetals TaAs, NbAs, and NdSb. A striking phenomenon is observed where the thermal conductivity shows a T scaling at very low temperatures, while the resistivity shows a T-independent residual term. This indicates a strong violation of the Wiedemann-Franz (WF) law, since the field dependence of κ shows that the low-temperature thermal conductivity is dominated by electronic transport. The obtained Lorenz ratio is hundreds of times lower than Sommerfeld's value even when approaching the zero-temperature limit. The strong downward deviation of the WF law at very low temperatures point to a non-Fermi liquid state in these materials. In addition, the giant thermal quantum oscillations accompanied by antiphase characteristics have been observed. Our findings not only point to a possible non-Fermi liquid ground state of these topological compensated semimetals, but also reveal an unusual T temperature dependence for the electronic thermal conductivity.
在拓扑补偿半金属TaAs、NbAs和NdSb中研究了极低温和强磁场下的热导率和电阻率。观察到一个显著现象：在极低温下热导率呈现T标度，而电阻率呈现与T无关的残余项。这表明维德曼-夫兰兹（WF）定律被严重违反，因为κ的磁场依赖性表明低温热导率由电子输运主导。即使接近零温度极限，得到的洛伦兹比也比索末菲值低数百倍。在极低温下WF定律的强烈向下偏离表明这些材料处于非费米液体状态。此外，还观察到了伴有反相特征的巨大热量子振荡。我们的发现不仅指出了这些拓扑补偿半金属可能存在非费米液体基态，还揭示了电子热导率对温度T的异常依赖性。
