Magnetotransport Properties of a Nodal Line Semimetal TiSi**Supported by the National Key Research Program of China under Grant Nos 2016YFA0401000 and 2016YFA0300604, the National Basic Research Program of China under Grant No 2015CB921303, the Strategic Priority Research Program (B) of Chinese Academy of Sciences under Grant No XDB07020100, and the National Natural Science Foundation of China under Grant No 11874417.

Abstract

We report the magnetoresistance (MR), de Haas-van Alphen (dHvA) effect and Hall effect measurements on a single crystal of TiSi, which is predicted to be a nodal line semimetal. With application of a magnetic field, a metal-to-insulator-like transition in ρ(T) and a nonsaturating MR are observed at low temperatures. The dHvA oscillations reveal a small Fermi-surface pocket with a nontrivial Berry phase. The analysis of the nonlinear Hall resistivity shows that TiSi is a multiband system with low carrier densities and high mobilities. All these results unambiguously prove the existence of Dirac fermions in TiSi.