Unconventional mass enhancement around the Dirac nodal loop in ZrSiS
Unconventional mass enhancement around the Dirac nodal loop in ZrSiS
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DOI：
10.1038/nphys4306
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发表时间：
2018-02-01
期刊：
影响因子：
19.6
通讯作者：
Wiedmann, S.
中科院分区：
文献类型：
--
作者：
Pezzini, S.;van Delft, M. R.;Wiedmann, S.
费米子的拓扑性质来自于它们的低能类狄拉克带色散和相关的手征。最初仅限于点，狄拉克色散扩展到线，甚至环路，现在已经被发现，并且已经确定了承载这些功能的半金属。然而，实验证据的增强相关效应预测发生在这些拓扑半金属一直缺乏。在这里，我们报告了一个量子振荡的研究，揭示了显着增强的准粒子的有效质量附近的节环的高磁场中的半金属ZrSiS。在阈值场以上，磁击穿发生在环结构中的间隙上，其轨道围绕其顶点包围不同的绕组，每个绕组伴随着额外的π Berry相位。这些击穿轨道的振幅表现出异常的温度依赖性。这些发现表明，出现了新的，相关驱动的物理学在ZrSiS与Dirac类准粒子。
The topological properties of fermions arise from their low-energy Dirac-like band dispersion and associated chirality. Initially confined to points, extensions of the Dirac dispersion to lines, and even loops, have now been uncovered, and semimetals hosting such features have been identified. However, experimental evidence for the enhanced correlation effects predicted to occur in these topological semimetals has been lacking. Here, we report a quantum oscillation study of the nodal-loop semimetal ZrSiS in high magnetic fields that reveals significant enhancement in the effective mass of the quasiparticles residing near the nodal loop. Above a threshold field, magnetic breakdown occurs across gaps in the loop structure with orbits that enclose different windings around its vertices, each winding accompanied by an additional pi Berry phase. The amplitudes of these breakdown orbits exhibit an anomalous temperature dependence. These findings demonstrate the emergence of novel, correlation-driven physics in ZrSiS associated with the Dirac-like quasiparticles.