Anomalous electronic structure and magnetoresistance in TaAs2.
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, e.g., 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 TaAs2 possesses a very large negative magnetoresistance, with an unknown scattering mechanism. Density functional calculations find that TaAs2 is a new topological semimetal [ℤ2 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.
Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
Yongkang
Y
Luo
Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
R D
RD
McDonald
Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
P F S
PF
Rosa
Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
B
B
Scott
Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
N
N
Wakeham
Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
N J
NJ
Ghimire
Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
E D
ED
Bauer
Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
J D
JD
Thompson
Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
F
F
Ronning