Quantum oscillations and nontrivial topological state in a compensated semimetal TaP2

Autor: Hongyuan Wang, Wei Xia, Na Yu, Jiuyang Zhang, Xiaofei Hou, Zhenhai Yu, Xia Wang, Yanfeng Guo, Qifeng Liang, Yishi Lin, Xiaolei Liu, Yuhua Zhen, Zhiqiang Zou, Hao Su, Yihua Wang
Rok vydání: 2019
Předmět:
Zdroj: Physical Review B. 100
ISSN: 2469-9969
2469-9950
Popis: We report systematic magneto-transport measurements and ab initio calculations on single-crystalline TaP2, a new member of the transition-metal dipnictides. We observed unsaturated magnetoresistance (MR) reaching ~ 700% at a magnetic field (B) of 9 T at 2 K along with striking Shubnikov-de Hass (SdH) oscillations. Our analysis on the SdH oscillations reveals nonzero Berry phase, indicating nontrivial band topology. The analysis also uncovers three fundamental magnetic oscillation frequencies of 72 T, 237 T, and 356 T, consistent with the theoretical calculations which reveal one hole pocket and two electron pockets at the L point and one electron pocket at the Z point of the Brillouin zone. We also found negative longitudinal MR (n-MR) within a narrow window of the angles between B and the electric current (I). The n-MR could be fitted with the Adler-Bell-Jackiw chiral anomaly equation but the origin remains yet ambiguous. The ab inito calculations suggest TaP2 as a weak topological insulator with the Z2 indices of (0; 111), which exhibits topological surface states on the (001) surface.
22 pages, 6 figures, 1 table
Databáze: OpenAIRE