Correlation-driven electronic nematicity in the Dirac semimetal BaNiS2

Christopher John Butler, Yuhki Kohsaka, Youichi Yamakawa, Mohammad Saeed Bahramy, Seiichiro Onari, Hiroshi Kontani, Tetsuo Hanaguri, Shinichi Shamoto

研究成果: Article同行評審

1 引文 斯高帕斯(Scopus)


In BaNiS2, a Dirac nodal line band structure exists within a two-dimensional Ni square lattice system, in which significant electronic correlation effects are anticipated. Using scanning tunneling microscopy (STM), we discover signs of correlated-electron behavior, namely electronic nematicity appearing as a pair of C2-symmetry striped patterns in the local density-of-states at ∼60 meV above the Fermi energy. In observations of quasiparticle interference, as well as identifying scattering between Dirac cones, we find that the striped patterns in real space stem from a lifting of degeneracy among electron pockets at the Brillouin zone boundary. We infer a momentum-dependent energy shift with d-form factor, which we model numerically within a density wave (DW) equation framework that considers spin-fluctuation-driven nematicity. This suggests an unusual mechanism driving the nematic instability, stemming from only a small perturbation to the Fermi surface, in a system with very low density of states at the Fermi energy. The Dirac points lie at nodes of the d-form factor and are almost unaffected by it. These results highlight BaNiS2 as a unique material in which Dirac electrons and symmetry-breaking electronic correlations coexist.

期刊Proceedings of the National Academy of Sciences of the United States of America
出版狀態Published - 2022 12月 6

All Science Journal Classification (ASJC) codes

  • 多學科


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