Ultrahigh mobility and giant magnetoresistance in the Dirac semimetal Cd3As2
Ultrahigh mobility and giant magnetoresistance in the Dirac semimetal Cd3As2
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DOI：
10.1038/nmat4143
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发表时间：
2015-03-01
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：
Liang, Tian;Gibson, Quinn;Ong, N. P.
狄拉克和外尔半金属是石墨烯的3D类似物，其中晶体对称性保护节点免受间隙形成（1-3）。Na 3Bi和Cd 3As 2被预测为狄拉克半金属（4，5），最近通过光电发射实验证实了这一点（6-8）。已经提出了狄拉克半金属在磁场中的几种新的输运性质（2，9 -11）。在这里，我们报告的性质Cd 3As 2是不可预测的，即一个显着的保护机制，强烈抑制反向散射在零磁场。在单晶中，保护导致在5 K下的载流子迁移率为9 × 10（6）cm（2）V-1 s（-1）。反向散射的抑制导致传输寿命比量子寿命长10（4）倍。通过施加的磁场解除这种保护导致非常大的磁阻。我们讨论了如何这可能涉及到费米面的变化所施加的磁场。
Dirac and Weyl semimetals are 3D analogues of graphene in which crystalline symmetry protects the nodes against gap formation(1-3). Na3Bi and Cd3As2 were predicted to be Dirac semimetals(4,5), and recently confirmed to be so by photoemission experiments(6-8). Several novel transport properties in a magnetic field have been proposed for Dirac semimetals(2,9-11). Here, we report a property of Cd3As2 that was unpredicted, namely a remarkable protection mechanism that strongly suppresses backscattering in zero magnetic field. In single crystals, the protection results in ultrahigh mobility, 9 x 10(6) cm(2) V-1 s(-1) at 5 K. Suppression of backscattering results in a transport lifetime 10(4) times longer than the quantum lifetime. The lifting of this protection by the applied magnetic field leads to a very large magnetoresistance. We discuss how this may relate to changes to the Fermi surface induced by the applied magnetic field.