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

doi:10.1126/science.aaz3480

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

Physics

Research output: Contribution to journal › Article › peer-review

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 language	English (US)
Pages (from-to)	179-183
Number of pages	5
Journal	Science
Volume	369
Issue number	6500
DOIs	https://doi.org/10.1126/science.aaz3480
State	Published - Jul 10 2020

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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

Schröter, NBM, Stolz, S, Manna, K, De Juan, F, Vergniory, MG, Krieger, JA, Pei, D, Schmitt, T, Dudin, P, Kim, TK, Cacho, C, Bradlyn, B, Borrmann, H, Schmidt, M, Widmer, R, Strocov, VN & Felser, C 2020, 'Observation and control of maximal Chern numbers in a chiral topological semimetal', Science, vol. 369, no. 6500, pp. 179-183. https://doi.org/10.1126/science.aaz3480

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title = "Observation and control of maximal Chern numbers in a chiral topological semimetal",

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.",

author = "Schr{\"o}ter, {Niels B.M.} and Samuel Stolz and Kaustuv Manna and {De Juan}, Fernando and Vergniory, {Maia G.} and Krieger, {Jonas A.} and Ding Pei and Thorsten Schmitt and Pavel Dudin and Kim, {Timur K.} and Cephise Cacho and Barry Bradlyn and Horst Borrmann and Marcus Schmidt and Roland Widmer and Strocov, {Vladimir N.} and Claudia Felser",

note = "K.M. and C.F. acknowledge financial support from the European Research Council (ERC) Advanced Grant nos. 291472 \{"}Idea Heusler\{"} and 742068 \{"}TOP-MAT\{"}, and Deutsche Forschungsgemeinschaft (project ID 258499086 and FE 633/30-1). N.B.M.S. was supported by Microsoft. M.G.V. acknowledges support from DFG INCIEN2019-000356 from Gipuzkoako Foru Aldundia. S.S. and R.W. acknowledge funding from the Swiss National Science Foundation under SNSF project number 159690. D.P. acknowledges support from the Chinese Scholarship Council. J.A.K. acknowledges support from the Swiss National Science Foundation (SNF-grant no. 200021-165910).",

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doi = "10.1126/science.aaz3480",

language = "English (US)",

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T1 - Observation and control of maximal Chern numbers in a chiral topological semimetal

AU - Schröter, Niels B.M.

AU - Stolz, Samuel

AU - Manna, Kaustuv

AU - De Juan, Fernando

AU - Vergniory, Maia G.

AU - Krieger, Jonas A.

AU - Pei, Ding

AU - Schmitt, Thorsten

AU - Dudin, Pavel

AU - Kim, Timur K.

AU - Cacho, Cephise

AU - Bradlyn, Barry

AU - Borrmann, Horst

AU - Schmidt, Marcus

AU - Widmer, Roland

AU - Strocov, Vladimir N.

AU - Felser, Claudia

N1 - K.M. and C.F. acknowledge financial support from the European Research Council (ERC) Advanced Grant nos. 291472 \"Idea Heusler\" and 742068 \"TOP-MAT\", and Deutsche Forschungsgemeinschaft (project ID 258499086 and FE 633/30-1). N.B.M.S. was supported by Microsoft. M.G.V. acknowledges support from DFG INCIEN2019-000356 from Gipuzkoako Foru Aldundia. S.S. and R.W. acknowledge funding from the Swiss National Science Foundation under SNSF project number 159690. D.P. acknowledges support from the Chinese Scholarship Council. J.A.K. acknowledges support from the Swiss National Science Foundation (SNF-grant no. 200021-165910).

PY - 2020/7/10

Y1 - 2020/7/10

N2 - 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.

AB - 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.

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

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