Bias-Free Access to Orbital Angular Momentum in Two-Dimensional Quantum Materials

Research output: Contribution to journalResearch articleContributedpeer-review


  • Jonas Erhardt - , University of Würzburg (Author)
  • Cedric Schmitt - , University of Würzburg (Author)
  • Philipp Eck - , University of Würzburg (Author)
  • Matthias Schmitt - , University of Würzburg, Diamond Light Source (Author)
  • Philipp Keßler - , University of Würzburg (Author)
  • Kyungchan Lee - , University of Würzburg (Author)
  • Timur Kim - , Diamond Light Source (Author)
  • Cephise Cacho - , Diamond Light Source (Author)
  • Iulia Cojocariu - , Sincrotrone Trieste, Jülich Research Centre, University of Trieste (Author)
  • Daniel Baranowski - , Jülich Research Centre (Author)
  • Vitaliy Feyer - , Jülich Research Centre, University of Duisburg-Essen (Author)
  • Louis Veyrat - , University of Würzburg, Leibniz Institute for Solid State and Materials Research Dresden, French National Centre for Scientific Research (CNRS), Würzburg-Dresden Cluster of Excellence ct.qmat (Author)
  • Giorgio Sangiovanni - , University of Würzburg (Author)
  • Ralph Claessen - , University of Würzburg (Author)
  • Simon Moser - , University of Würzburg (Author)


The demonstration of a topological band inversion constitutes the most elementary proof of a quantum spin Hall insulator (QSHI). On a fundamental level, such an inverted band gap is intrinsically related to the bulk Berry curvature, a gauge-invariant fingerprint of the wave function's quantum geometric properties in Hilbert space. Intimately tied to orbital angular momentum (OAM), the Berry curvature can be, in principle, extracted from circular dichroism in angle-resolved photoemission spectroscopy (CD-ARPES), were it not for interfering final state photoelectron emission channels that obscure the initial state OAM signature. Here, we outline a full-experimental strategy to avoid such interference artifacts and isolate the clean OAM from the CD-ARPES response. Bench-marking this strategy for the recently discovered atomic monolayer system indenene, we demonstrate its distinct QSHI character and establish CD-ARPES as a scalable bulk probe to experimentally classify the topology of two-dimensional quantum materials with time reversal symmetry.


Original languageEnglish
Article number196401
JournalPhysical review letters
Issue number19
Publication statusPublished - 10 May 2024


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