Observation and control of maximal Chern numbers in a chiral topological semimetal

Niels B.M. Schröter, Samuel Stolz, Kaustuv Manna, Fernando De Juan, Maia G. Vergniory, Jonas A. Krieger, Ding Pei, Thorsten Schmitt, Pavel Dudin, Timur K. Kim, Cephise Cacho, Barry Bradlyn, Horst Borrmann, Marcus Schmidt, Roland Widmer, Vladimir N. Strocov, Claudia Felser

Research output: Contribution to journalArticle

Abstract

Topological semimetals feature protected nodal band degeneracies characterized by a topological invariant known as the Chern number (C). Nodal band crossings with linear dispersion are expected to have at most |C| = 4, which sets an upper limit to the magnitude of many topological phenomena in these materials. Here, we show that the chiral crystal palladium gallium (PdGa) displays multifold band crossings, which are connected by exactly four surface Fermi arcs, thus proving that they carry the maximal Chern number magnitude of 4. By comparing two enantiomers, we observe a reversal of their Fermi-arc velocities, which demonstrates that the handedness of chiral crystals can be used to control the sign of their Chern numbers.

Original languageEnglish (US)
Pages (from-to)179-183
Number of pages5
JournalScience
Volume369
Issue number6500
DOIs
StatePublished - Jul 10 2020

ASJC Scopus subject areas

  • General

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    Schröter, N. B. M., Stolz, S., Manna, K., De Juan, F., Vergniory, M. G., Krieger, J. A., Pei, D., Schmitt, T., Dudin, P., Kim, T. K., Cacho, C., Bradlyn, B., Borrmann, H., Schmidt, M., Widmer, R., Strocov, V. N., & Felser, C. (2020). Observation and control of maximal Chern numbers in a chiral topological semimetal. Science, 369(6500), 179-183. https://doi.org/10.1126/science.aaz3480