Publications by authors named "Philipp Eck"
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.
View Article and Find Full Text PDFAtomic monolayers on semiconductor surfaces represent an emerging class of functional quantum materials in the two-dimensional limit - ranging from superconductors and Mott insulators to ferroelectrics and quantum spin Hall insulators. Indenene, a triangular monolayer of indium with a gap of ~ 120 meV is a quantum spin Hall insulator whose micron-scale epitaxial growth on SiC(0001) makes it technologically relevant. However, its suitability for room-temperature spintronics is challenged by the instability of its topological character in air.
View Article and Find Full Text PDFEngineering surfaces and interfaces of materials promises great potential in the field of heterostructures and quantum matter designers, with the opportunity to drive new many-body phases that are absent in the bulk compounds. Here, we focus on the magnetic Weyl kagome system CoSnS and show how for the terminations of different samples the Weyl points connect differently, still preserving the bulk-boundary correspondence. Scanning tunneling microscopy has suggested such a scenario indirectly, and here, we probe the Fermiology of CoSnS directly, by linking it to its real space surface distribution.
View Article and Find Full Text PDFStructural moiré superstructures arising from two competing lattices may lead to unexpected electronic behavior. Sb is predicted to show thickness-dependent topological properties, providing potential applications for low-energy-consuming electronic devices. Here we successfully synthesize ultrathin Sb films on semi-insulating InSb(111)A.
View Article and Find Full Text PDFArticle Synopsis
- Large-gap quantum spin Hall insulators, which utilize Dirac fermions, are being explored for room-temperature applications, primarily due to their strong spin-orbit interaction.
- A common method to create these materials involves using monolayers of heavy atoms on hexagonal templates; however, this often results in triangular lattices that usually do not support the desired properties.
- The study introduces "indenene," a triangular monolayer of indium on SiC, which demonstrates unique valley physics and the quantum spin Hall phase despite its triangular structure, revealing underlying honeycomb characteristics through specific wave function behaviors.
Article Synopsis
- The Rashba effect is key to understanding two-dimensional electron systems and is crucial for various spintronic applications.
- This study provides strong experimental support for the idea that orbital angular momentum (OAM) in Bloch wave functions is responsible for the Rashba effect in a monolayer of AgTe on Ag(111).
- By employing advanced techniques like angle-resolved photoemission (ARPES) and low-energy electron diffraction, researchers establish a clear link between OAM and Rashba spin splittings in AgTe's electronic bands.
Article Synopsis
- TaAs and TaP are recognized as Weyl semimetals, but understanding their surface features and Fermi arcs related to their bulk Weyl points has been a challenge.
- * The study combines linear dichroism in angle-resolved photoemission with first-principles calculations to investigate the orbital texture on the Fermi surface of TaP(001).
- * The researchers identify distinct changes in orbital texture at Weyl nodes, demonstrating the importance of orbital degrees of freedom in connecting surface and bulk properties in Weyl semimetals.*