AI 中文总结
研究重费米子化合物UPd$_2$Al$_3$在反铁磁态至18T metamagnetic 相变点的热电信号磁场依赖，结合重整化微扰理论分析发现，塞曼效应驱动费米面拓扑变化，$H_\text{M}$处存在费米面重构。
AI 中文摘要
我们报道了重费米子化合物UPd$_2$Al$_3$在低温下的连续反常现象，该现象存在于反铁磁态内，直至 metamagnetic 相变点$H_\text{M}=18$T，体现在热电信号的磁场依赖关系中。基于重整化微扰理论，并将f轨道划分为局域与离域部分，我们的分析将这些反常归因于塞曼效应驱动的费米面复杂拓扑变化。在$H_\text{M}$处，热电势和霍尔系数均出现符号突变，且$H_\text{M}$以上热电势中出现大量量子振荡，这些观测结果表明，由于电子能带的展开， metamagnetic 相变处发生了强烈的费米面重构。
英文摘要
We report successive anomalies at low temperature in the magnetic field dependence of the thermoelectric signal in the heavy fermion compound UPd$_{2}$Al$_{3}$ inside the antiferromagnetic state up to the metamagnetic transition at $H_\text{M} =18$~T. Based on renormalisation perturbation theory and the partitioning of the $f$ orbitals into localized and delocalized parts, our analysis attributes these anomalies to complex topological changes of the Fermi surface driven by Zeeman effect. The observation of a sudden change of sign both in the thermoelectric power and in the Hall coefficient at $H_\text{M}$ in addition to the appearance of large quantum oscillations in the thermoelectric power above $H_\text{M}$ indicate a strong Fermi surface reconstruction at the metamagnetic transition due to the unfolding of the electronic bands.
Comments14 pages, 12 figures
