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Observation and control of maximal Chern numbers in a chiral topological semimetal
Authors:
Niels B. M.
Schroeter
(Swiss Light Source)
,
Samuel
Stolz
(EMPA, Swiss Federal Laboratories for Materials Science and Technology; EPFL)
,
Kaustuv
Manna
(Max Planck Institute for Chemical Physics of Solids)
,
Fernando
De Juan
(Donostia International Physics Center; IKERBASQUE, Basque Foundation for Science)
,
Maia G.
Vergniory
(Donostia International Physics Center; IKERBASQUE, Basque Foundation for Science)
,
Jonas A.
Krieger
(Swiss Light Source; Paul Scherrer Institute; ETH Zurich)
,
Ding
Pei
(University of Oxford)
,
Thorsten
Schmitt
(Swiss Light Source)
,
Pavel
Dudin
(Diamond Light Source)
,
Timur K.
Kim
(Diamond Light Source)
,
Cephise
Cacho
(Diamond Light Source)
,
Barry
Bradlyn
(University of Illinois at Urbana-Champaign)
,
Horst
Borrmann
(Max Planck Institute for Chemical Physics of Solids)
,
Marcus
Schmidt
(Max Planck Institute for Chemical Physics of Solids)
,
Roland
Widmer
(EMPA, Swiss Federal Laboratories for Materials Science and Technology)
,
Vladimir N.
Strocov
(Swiss Light Source)
,
Claudia
Felser
(Max Planck Institute for Chemical Physics of Solids)
Co-authored by industrial partner:
No
Type:
Journal Paper
Journal:
Science
, VOL 369
, PAGES 179 - 183
State:
Published (Approved)
Published:
July 2020
Diamond Proposal Number(s):
24703
,
20617

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 | 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.
Subject Areas:
Physics,
Materials
Instruments:
I05-ARPES
Documents:
179.full.pdf
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Technical Tags: