Electronic structure at 2D–metal interfaces: from ARPES to superconducting junctions

Date

Oct 7, 2026

Time

1:00 PM - 2:00 PM

Speaker

Dr. Nagireddi Laxman

Affiliation

CNRS, Thales, Université Paris-Saclay

Language

en

Main Topic

Materialien

Host

Rita Taubert

Description

Understanding the interface between metals and two-dimensional materials is critical for their application in electronics, and requires model systems in which the roughness, purity and crystallinity of the metal surface can be controlled. Template-stripped gold provides such a platform, and this talk uses it to show how a metal substrate reshapes the electronic structure of the layer above it. Here, we use angle-resolved photoemission spectroscopy to investigate the layer-dependent electronic structure of WSe2 on template-stripped gold (TSG) substrates [1], fabricated using both silicon and mica templates to give disordered and Au(111)-ordered surfaces. Strong hybridisation around Γ points to a covalent admixture in the gold-WSe2 interaction. In addition, band shifts indicate charge rearrangement at the interface. Core-level spectroscopy resolves a single chemical environment for the interfacial WSe2 layer, distinct from the layers above. The interaction is best described as covalent-like quasi-bonding of intermediate strength. Building upon the same preparation route, we study the electronic structure of the two-dimensional magnetic semiconductor CrSBr in both the bulk [2] and monolayer [3] limits. In bulk, the electronic structure can be followed from the antiferromagnetic ground state into the paramagnetic phase, revealing pairs of states at X whose splitting disappears above TN =132 K and is interpreted as an effective exchange splitting within individual layers. In the monolayer limit the substrate plays a far more active role: charge transfer populates the conduction band, the quasiparticle gap is strongly reduced, and the two conduction bands split at X, signalling a breaking of the glide-mirror symmetry that protects this degeneracy in the free-standing monolayer. TSG therefore does more than modify carrier density and screening: it can lift symmetry-protected degeneracies and reshape the band topology itself. This concern with interface quality extends from spectroscopy to transport in current work at CNRS–Thales, on heterostructures combining high-Tc d-wave superconductors with 2D transition-metal dichalcogenides for studies of the superconducting proximity effect [4]. References [1] L. Nagireddy et al., 2D Mater. 12, 045017 (2025). [2] M. D. Watson et al., npj 2D Mater. Appl. 8, 54 (2024). [3] Y. P. Ghimirey et al., npj 2D Mater. Appl. 10, 26 (2026). [4] D. Perconte et al., Nat. Phys. 14, 25 (2018).

Links

• Seminars at the IFW

Last modified: Sep 24, 2026, 7:37:46 AM