Nontrivial Giant Linear Magnetoresistance in Nodal-Line Semimetal ZrGeSe 2D Layers.

Yang, Jie; Song, Zhi-Yong; Guo, Lei; Gao, Heng; Dong, Zhuo; Yu, Qiang; Zheng, Ren-Kui; Kang, Ting-Ting et al. · Nano Lett · 2021

basic_science · Level V

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Abstract

Linear magnetoresistance (LMR) is usually observed in topological quantum materials and plausibly connected with the topologically nontrivial surface state with Dirac-cone-like linear dispersion because the frequently encountered large Hall resistivity can be trivially mixed into the LMR via charge inhomogeneity. Herein, by applying an optimal gate voltage to nodal-line semimetal ZrGeSe two-dimensional (2D) layers with specific thicknesses, we observe a giant nonsaturated LMR of 8 × 10<sup>4</sup>% at 2 K and a magnetic field of 9 T. This giant LMR is accompanied by a very small Hall resistivity, which is inconsistent with the charge inhomogeneity mechanism. Our systematic results confirm that the giant LMR is maximized when the topological semimetal is in the "even-metal" regime and suppressed upon evolution to the normal "odd-metal" regime. The "even-to-odd" transition is universal regardless of the thicknesses of the crystals. A comparison with Abrikosov's quantum LMR theory indicates that the observed LMR cannot be trivial.