Anomalous electronic structure and magnetoresistance in TaAs2

作者：Luo Yongkang; McDonald R D; Rosa P F S; Scott B; Wakeham N; Ghimire N J; Bauer E D; Thompson J D; Ronning F

来源：Scientific Reports, 2016, 6(1): 27294.

DOI：10.1038/srep27294

<jats:title>Abstract</jats:title><jats:p>The change in resistance of a material in a magnetic field reflects its electronic state. In metals with weakly- or non-interacting electrons, the resistance typically increases upon the application of a magnetic field. In contrast, negative magnetoresistance may appear under some circumstances, <jats:italic>e.g.</jats:italic>, in metals with anisotropic Fermi surfaces or with spin-disorder scattering and semimetals with Dirac or Weyl electronic structures. Here we show that the non-magnetic semimetal TaAs<jats:sub>2</jats:sub> possesses a very large negative magnetoresistance, with an unknown scattering mechanism. Density functional calculations find that TaAs<jats:sub>2</jats:sub> is a new topological semimetal [ℤ<jats:sub>2</jats:sub> invariant (0;111)] without Dirac dispersion, demonstrating that a negative magnetoresistance in non-magnetic semimetals cannot be attributed uniquely to the Adler-Bell-Jackiw chiral anomaly of bulk Dirac/Weyl fermions.</jats:p>

• 出版日期2016-6-7