Ultraquantum magnetoresistance in the Kramers-Weyl semimetal candidate β-Ag2Se

Cheng Long Zhang, Frank Schindler, Haiwen Liu, Tay Rong Chang, Su Yang Xu, Guoqing Chang, Wei Hua, Hua Jiang, Zhujun Yuan, Junliang Sun, Horng Tay Jeng, Hai Zhou Lu, Hsin Lin, M. Zahid Hasan, X. C. Xie, Titus Neupert, Shuang Jia

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14 Scopus citations

Abstract

The topological semimetal β-Ag2Se features a Kramers-Weyl node at the origin in momentum space and a quadruplet of spinless Weyl nodes, which are annihilated by spin-orbit coupling. We show that single-crystalline β-Ag2Se manifests giant Shubnikov-de Haas oscillations in the longitudinal magnetoresistance, which stem from a small electron pocket that can be driven beyond the quantum limit by a field less than 9 T. This small electron pocket is a remainder of the spin-orbit annihilated Weyl nodes and thus encloses a Berry-phase structure. Moreover, we observed a negative longitudinal magnetoresistance when the magnetic field is beyond the quantum limit. Our experimental findings are complemented by thorough theoretical band-structure analyses of this Kramers-Weyl semimetal candidate, including first-principles calculations and an effective k·p model.

Original languageEnglish (US)
Article number165148
JournalPhysical Review B
Volume96
Issue number16
DOIs
StatePublished - Oct 26 2017

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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    Zhang, C. L., Schindler, F., Liu, H., Chang, T. R., Xu, S. Y., Chang, G., Hua, W., Jiang, H., Yuan, Z., Sun, J., Jeng, H. T., Lu, H. Z., Lin, H., Hasan, M. Z., Xie, X. C., Neupert, T., & Jia, S. (2017). Ultraquantum magnetoresistance in the Kramers-Weyl semimetal candidate β-Ag2Se. Physical Review B, 96(16), [165148]. https://doi.org/10.1103/PhysRevB.96.165148