2018/03/10 by Amit, Radha Krishna Gopal, Gopal, R. K. +2
Physics and Astronomy · #Advanced Condensed Matter Physics #FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci) #Quantum many-body systems #Strongly Correlated Electrons (cond-mat.str-el) #Topological Materials and Phenomena
paper · pdf · doi:10.48550/arxiv.1803.03825
openalex publication_date 2018/03/10 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Bi1-xSbx is a topological insulator (TI) for x ≈ 0.03 --0.20. Close to the Topological phase transition at x = 0.03, a magnetic field induced Weyl semi-metal (WSM) state is stabilized due to the splitting of the Dirac cone into two Weyl cones of opposite chirality. A signature of the Weyl state is the observation of a Chiral anomaly [negative longitudnal magnetoresistance (LMR)] and a violation of the Ohm's law (non-linear I-V). We report the unexpected discovery of a Chiral anomaly in the whole range (x = 0.032, 0.072, 0.16) of the TI state. This points to a field induced WSM state in an extended x range and not just near the topological transition at x = 0.03. Surprisingly, the strongest Weyl phase is found at x = 0.16 with a non-saturating negative LMR much larger than observed for x = 0.03. The negative LMR vanishes rapidly with increasing angle between B and I. Additionally, non-linear I--V is found for x = 0.16 indicating a violation of Ohm's law. This unexpected observation of a strong Weyl state in the whole TI regime in Bi1-xSbx points to a gap in our understanding of the detailed electronic structure evolution in this alloy system.