拓扑半金属ZrSiSe器件中面内霍尔效应的观测

Observation of planar Hall effect in topological semimetal ZrSiSe device

拓扑半金属中的手性反常通常是用负磁阻来检测.然而,手性反常导致的负磁阻对磁场和电流的夹角比较敏感,这给测量带来了挑战.最近,作为一种新兴实验手段,面内霍尔效应被越来越多地应用于拓扑半金属中手性反常的探测.本文通过将拓扑Nodal-line半金属ZrSiSe块体机械剥离制备成的介观器件,对其面内霍尔效应进行了测量并探究其起源.尽管测量数据与拓扑半金属中手性反常导致的面内霍尔效应理论公式拟合得很好,但各向异性磁电阻的分析结果表明,负磁阻并不存在.更进一步地,根据最近报道提出手性反常存在的判据,在一个手性反常主导的系统中,以磁场和电流夹角为参数的Rxx-Ryx关系曲线呈现为随磁场变化的一系列同心圆,而在本文ZrSiSe器件的输运实验中,表现为非同心圆的形式.结合分析,本文排除了手性反常的存在,并推断各向异性磁电阻才是其面内霍尔效应的起因.

Planar Hall effect(PHE)is a newly emerging experimental tool to detect chiral anomaly and nontrivial Berry curvature in topological semimetals,as chiral-anomaly-induced negative magnetoresistance is sensitive to the angle between magnetic field B and current I.Here we demonstrate the PHE in a topological nodal-line semimetal ZrSiSe device by electric transport measurement.According to our analysis,we conclude that the PHE results from the trivial anisotropic magnetoresistance(AMR).We argue that there is no inevitability between PHE and chiral anomaly,and some other mechanisms can induce PHE.This work indicates that PHE cannot be considered as evidence of chiral anomaly and one may seek for non-topological origin in such studies.