Room-temperature magnetic topological Weyl fermion and nodal line semimetal states in half-metallic Heusler Co2 TiX (X=Si, Ge, or Sn)

Guoqing Chang, Su Yang Xu, Hao Zheng, Bahadur Singh, Chuang Han Hsu, Guang Bian, Nasser Alidoust, Ilya Belopolski, Daniel S. Sanchez, Songtian Zhang, Hsin Lin, M. Zahid Hasan

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103 Scopus citations


Topological semimetals (TSMs) including Weyl semimetals and nodal-line semimetals are expected to open the next frontier of condensed matter and materials science. Although the first inversion breaking Weyl semimetal was recently discovered in TaAs, its magnetic counterparts, i.e., the time-reversal breaking Weyl and nodal line semimetals, remain elusive. They are predicted to exhibit exotic properties distinct from the inversion breaking TSMs including TaAs. In this paper, we identify the magnetic topological semimetal states in the ferromagnetic half-metal compounds Co2 TiX (X = Si, Ge, or Sn) with Curie temperatures higher than 350 K. Our first-principles band structure calculations show that, in the absence of spin-orbit coupling, Co2 TiX features three topological nodal lines. The inclusion of spin-orbit coupling gives rise to Weyl nodes, whose momentum space locations can be controlled as a function of the magnetization direction. Our results not only open the door for the experimental realization of topological semimetal states in magnetic materials at room temperature, but also suggest potential applications such as unusual anomalous Hall effect in engineered monolayers of the Co2 TiX compounds at high temperature.

Original languageEnglish (US)
Article number38839
JournalScientific reports
StatePublished - Dec 15 2016

All Science Journal Classification (ASJC) codes

  • General


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