Evidence for topological semimetallicity in a chain-compound TaSe3
Ahmad Ikhwan Us Saleheen, Ramakanta Chapai, Lingyi Xing, Roshan Nepal, Dongliang Gong, Xin Gui, Weiwei Xie, David P. Young, E. W. Plummer, Rongying Jin
Abstract
Abstract Among one-dimensional transition-metal trichalcogenides, TaSe 3 is unconventional in many respects. One is its strong topological semimetallicity as predicted by first-principles calculations. We report the experimental investigations of the electronic properties of one-dimensional-like TaSe 3 single crystals. While the b -axis electrical resistivity shows good metallicity with a high residual resistivity ratio greater than 100, an extremely large magnetoresistance is observed reaching ≈7 × 10 3 % at 1.9 K for 14 T. Interestingly, the magnetoresistance follows the Kohler’s rule with nearly quadratic magnetic field dependence, consistent with the electron–hole compensation scenario as confirmed by our Hall conductivity data. Both the longitudinal and Hall conductivities show Shubnikov-de Haas oscillations with two frequencies: F α ≈ 97 T and F β ≈ 186 T. Quantitative analysis indicates that F α results from the two-dimensional-like electron band with the non-trivial Berry phase [1.1 π ], and F β from the hole band with the trivial Berry phase [0(3D) − 0.16 π (2D)]. Our experimental findings are consistent with the predictions based on first-principles calculations.