Giant negative magnetoresistance induced by the chiral anomaly in individual Cd3As2 nanowires.
Giant negative magnetoresistance induced by the chiral anomaly in individual Cd3As2 nanowires.
复制标题
单个 Cd3As2 纳米线中手性异常引起的巨负磁阻
DOI：
10.1038/ncomms10137
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发表时间：
2015-12-17
影响因子：
16.6
通讯作者：
Yu DP
中科院分区：
文献类型：
--
作者：
Li CZ;Wang LX;Liu H;Wang J;Liao ZM;Yu DP
石墨烯和拓扑绝缘体以外的狄拉克电子材料最近引起了人们的极大关注。Cd3As2是一种沿三个动量方向都具有线性色散的狄拉克半金属，可以被视为石墨烯的三维类似物。通过打破时间反转对称性或空间反转对称性，狄拉克半金属被认为转变为具有奇异手征反常效应的Weyl半金属，然而手性反常的实验证据在Cd3As2中仍然缺失。在这里，我们显示了大的负磁电阻，在60 K时，−为63%，在300 K时为11%。负磁电阻可以通过调节费米能级上的手征态密度和Weyl节点间的谷间散射来调节栅极电压和温度。这些结果为手征反常效应提供了证据，对于理解狄拉克半金属中的Weyl费米子是有价值的。狄拉克半金属化合物具有三维线性的电子色散关系，使其成为石墨烯的三维类似物。在这里，作者报告了单晶Cd3As2纳米线中的大负磁电阻，证明了一种令人向往的手征反常效应。
Dirac electronic materials beyond graphene and topological insulators have recently attracted considerable attention. Cd3As2 is a Dirac semimetal with linear dispersion along all three momentum directions and can be viewed as a three-dimensional analogue of graphene. By breaking of either time-reversal symmetry or spatial inversion symmetry, the Dirac semimetal is believed to transform into a Weyl semimetal with an exotic chiral anomaly effect, however the experimental evidence of the chiral anomaly is still missing in Cd3As2. Here we show a large negative magnetoresistance with magnitude of −63% at 60 K and −11% at 300 K in individual Cd3As2 nanowires. The negative magnetoresistance can be modulated by gate voltage and temperature through tuning the density of chiral states at the Fermi level and the inter-valley scatterings between Weyl nodes. The results give evidence of the chiral anomaly effect and are valuable for understanding the Weyl fermions in Dirac semimetals. Dirac semimetals possess an electronic dispersion relation which is linear in three dimensions, making them three-dimensional analogues of graphene. Here, the authors report large negative magnetoresistance in single-crystal Cd3As2 nanowires, evidencing a sought-after chiral anomaly effect.