The chiral anomaly and thermopower of Weyl fermions in the half-Heusler GdPtBi
The chiral anomaly and thermopower of Weyl fermions in the half-Heusler GdPtBi
复制标题
DOI：
10.1038/nmat4684
复制
发表时间：
2016-11-01
期刊：
影响因子：
41.2
通讯作者：
Ong, N. P.
中科院分区：
文献类型：
--
作者：
Hirschberger, Max;Kushwaha, Satya;Ong, N. P.
狄拉克和外尔半金属是不寻常的材料，其中体态的节点被晶体对称性保护而不形成能隙（1-4）。手征异常（5，6），预计发生在两个系统（7-10），最近观察到的负纵向磁阻（LMR）在Na 3Bi（参考文献11）和TaAs（参考文献12）。一个重要的问题是外尔物理是否出现在更广泛的材料类别中。我们报告的证据手性异常的半Heusler GdPtBi。在零场中，GdPtBi是具有二次带的零带隙半导体（13，14）。在磁场中，塞曼能量导致外尔节点（15）。我们已经观察到一个大的负LMR与特定的手征异常的场导向性能。手征反常也引起了热电势的强烈抑制。本文详细研究了外尔费米子的热电响应函数α（xx）。从二次能带生成外尔节点的方案表明，手征异常可以在广泛的一类半金属中观察到。
The Dirac and Weyl semimetals are unusual materials in which the nodes of the bulk states are protected against gap formation by crystalline symmetry(1-4). The chiral anomaly(5,6), predicted to occur in both systems(7-10), was recently observed as a negative longitudinal magnetoresistance (LMR) in Na3Bi (ref. 11) and in TaAs (ref. 12). An important issue is whether Weyl physics appears in a broader class of materials. We report evidence for the chiral anomaly in the half-Heusler GdPtBi. In zero field, GdPtBi is a zero-gap semiconductor with quadratic bands(13,14). In a magnetic field, the Zeeman energy leads to Weyl nodes(15). We have observed a large negative LMR with the field-steering properties specific to the chiral anomaly. The chiral anomaly also induces strong suppression of the thermopower. We report a detailed study of the thermoelectric response function alpha(xx) of Weyl fermions. The scheme of creating Weyl nodes from quadratic bands suggests that the chiral anomaly may be observable in a broad class of semimetals.