Berlin 2024 – scientific programme
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O: Fachverband Oberflächenphysik
O 22: 2D Materials II: Electronic Structure (joint session O/TT)
O 22.2: Topical Talk
Tuesday, March 19, 2024, 10:45–11:15, MA 005
Bias free extraction of orbital angular momentum from two-dimensional materials by dichroic photoemission — Jonas Erhardt1,2, Cedric Schmitt1,2, Philipp Eck2,3, Philipp Kessler1,2, Kyungchan Lee1,2, Giorgio Sangiovanni2,3, Ralph Claessen1,2, and •Simon Moser1,2 — 1Physikalisches Institut, Universität Würzburg, D-97074 Würzburg, Germany — 2Würzburg-Dresden Cluster of Excellence ct.qmat, Universität Würzburg, D-97074 Würzburg, Germany — 3Institut für Theoretische Physik und Astrophysik, Universität Würzburg, D-97074 Würzburg, Germany
Topological band inversion is at the heart of the quantum spin Hall insulator (QSHI) but is difficult to demonstrate experimentally. In the bulk, this band inversion is characterized by the Berry curvature, a gauge-invariant fingerprint of the wave function's geometric properties. 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 photoelectron emission channels that obscure the 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 QSHI indenene, we establish CD ARPES as scale-able bulk probe to experimentally classify the topology of two dimensional quantum materials with time reversal symmetry.
Keywords: circular dichroism in ARPES (CD-ARPES); orbital angular momentum (OAM); quantum spin Hall insulator (QSHI); atomic monolayer