Negative Magnetoresistance in Topological Semimetals of Transition-Metal Dipnictides with Nontrivial Z2 Indices

Abstract

Negative magnetoresistance (NMR) induced by the Adler-Bell-Jackiw anomaly is regarded as the most prominent quantum signature of Weyl semimetals when electrical field $E$ is collinear with the external magnetic field $B$. In this article, we report universal NMR in nonmagnetic, centrosymmetric transition metal dipnictides MPn${}_2$ (M=Nb and Ta; Pn=As and Sb), in which the existence of Weyl fermions can be explicitly excluded. Using temperature-dependent magnetoresistance, Hall and thermoelectric coefficients of Nernst and Seebeck effects, we determine that the emergence of the NMR phenomena in MPn${}_2$ is coincident with a Lifshitz transition, corresponding to the formation of unique electron-hole-electron ($e$-$h$-$e$) pockets along the $I-L-I^{\prime }$ direction. First-principles calculations reveal that, along the $I-L-I^{\prime }$ line, the $d_{xy}$ and $d_{x^2-y^2}$ orbitals of the transition metal form tilted nodal rings of band crossing well below the Fermi level. Strong spin-orbital coupling gaps all the crossing points and creates the characteristic $e$-$h$-$e$ structure, making MPn${}_2$ a topological semimetal with ${\mathbb{Z}}_2$ indices of [0;(111)]. By excluding the weak localization contribution of the bulk states, we conclude that the universal NMR in MPn${}_2$ may have an exotic origin in topological surface states, which appears in pairs with opposite spin-momentum locking on nontrivial surfaces.

arXiv comment8 pages, 4 figures

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Cited by in corpus (7)

• On the search for the chiral anomaly in Weyl semimetals: The negative longitudinal magnetoresistance
• Negative Magnetoresistance in Weyl semimetals NbAs and NbP: Intrinsic Chiral Anomaly and Extrinsic Effects
• Optical Signatures of Dirac Nodal-lines in NbAs${}_2$
• Thermal chiral anomaly in the magnetic-field induced ideal Weyl phase of Bi1-xSbx topological insulators
• Magnetoresistance of compensated semimetals in confined geometries
• Magnetoresistance and robust resistivity plateau in MoAs2
• Anisotropic Fermi surface probed by the de Haas-van Alphen oscillation in proposed Dirac Semimetal TaSb${}_2$