Large unsaturated positive and negative magnetoresistance in Weyl semimetal TaP

Feb 24, 2016
Published in:
  • Sci.China Phys.Mech.Astron. 59 (2016) 5, 657406
  • Published: Feb 24, 2016

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Abstract: (Springer)
After successfully growing single-crystal TaP, we measured its longitudinal resistivity (ρxx_{xx} ) and Hall resistivity (ρyx_{yx} ) at magnetic fields up to 9 T in the temperature range of 2-300 K. At 8 T, the magnetoresistance (MR) reached 3.28 × 105^{5}% at 2 K, 176% at 300 K. Neither value appeared saturated. We confirmed that TaP is a hole-electron compensated semimetal with a low carrier concentration and high hole mobility of μh_{h}=3.71 × 105^{5} cm2^{2}/V s, and found that a magnetic-field-induced metal-insulator transition occurs at room temperature. Remarkably, because a magnetic field (H) was applied in parallel to the electric field (E), a negative MR due to a chiral anomaly was observed and reached -3000% at 9 T without any sign of saturation, either, which is in contrast to other Weyl semimetals (WSMs). The analysis of the Shubnikov-de Haas (SdH) oscillations superimposed on the MR revealed that a nontrivial Berry’s phase with a strong offset of 0.3958, which is the characteristic feature of charge carriers enclosing a Weyl node. These results indicate that TaP is a promising candidate not only for revealing fundamental physics of the WSM state but also for some novel applications.
  • Weyl semimetal
  • positive and negative magnetoresistance
  • Weyl fermions