ZrTe_(5)中的面内垂直电流方向的负磁阻现象

Perpendicular in-plane negative magnetoresistance in ZrTes

拓扑材料独特的能带结构有时会导致一些不同寻常的磁输运现象,其中包括当外磁场施加在平行电流方向上时产生的面内纵向负磁阻效应.这种负磁阻效应被普遍认为是拓扑材料中存在手征反常的一个标志.本文报道了一种当面内磁场分别平行和垂直电流方向时,在拓扑材料ZrTe_(5)中观察到的面内负磁阻现象.该现象揭示了一种超出手征反常范畴的不同寻常的量子输运行为.研究人员构建了一种同时考虑贝里曲率和轨道磁矩的普适模型,用以定量解释他们观察到的实验现象.本文的研究结果为探索拓扑材料中的面内负磁阻现象提供了一种新的见解和思路.

ZrTe5 exhibits a variety of topological phases,including Dirac semimetal[1],Weyl semimetal[2],strong topological insulator and weak topological insulator[3–6],as well as transitions between these phases[3,7–9].Such extraordinary complexity is due to the fact that the topological properties of ZrTe5 change with a slight variation in its lattice constant[3],making ZrTe5 an ideal platform for studying the electronic transport behavior of different topological phases and their transitions.In Weyl semimetals,an inplane magnetic field along the current direction can result in a charge pumping effect between the two different Weyl nodes,inducing a negative magnetoresistance(NMR)proportional to the square of the magnetic field B2,which is referred to the chiral anomaly[2,10].In general,such in-plane NMR is regarded as the most significant evidence of chiral anomaly[2,11].However,besides Weyl/Dirac semimetals,NMR has also been observed in some topological insulators and non-topological materials[12–14],in which chirality may not be well defined.In addition,there are other mechanisms that can also induce NMR,including spindependent scattering[15],weak localization[16],current jetting effect[14],transport in the quantum limit[1],and the effect of non-trivial band topology[12–14].Each of these mechanisms produces different transport characteristics,making it crucial to examine these characteristics when searching for the physical origin of NMR in a specific material.