![]() In a single layer MoS 2, absorption can reach up to 100 %, but the optical transition cannot be electrically tuned in such devices, as the excitons have essentially no out-of-plane dipole moment due to their confinement to a single layer. This can in principle be achieved via the quantum-confined Stark effect with an electric field applied perpendicular to the sample plane. The ability to additionally tune their transition energies is essential for various interesting opto-electronic applications based on light emission, detection, modulation and manipulation. Their optical properties are governed by excitons – electrons and holes bound by Coulomb attraction – that remain stable at room temperature. B 103, L201114 (2021)Ī strong and electrically tunable optical resonance in a two-dimensional semiconductorĪtomically thin transition metal dichalcogenides (TMDs), such as molybdenum disulfide (MoS 2), strongly interact with light. “Symmetry indicators for inversion-symmetric non-Hermitian topological band structures”, Phys. "Exceptional Topological Insulators”, Nat. Such a scenario is a natural result of strong electron-phonon interaction, paving the road for a future material discovery. For instance, the ETI phase emerges in a Weyl semimetal, when quasiparticles at the two Weyl nodes acquire finite but distinct lifetimes. The ETI can be induced universally in gapless solid-state systems and metamaterials, thereby setting a paradigm for non-Hermitian topological matter. Even though it does not require any symmetry to be stabilized, we explain how this non-Hermitian topological phase can also be inferred using symmetry-indicators of the bulk Hamiltonian. It covers the bulk energy point gap as a single sheet of complex eigenvalues or with a single exceptional point. Like the single surface Dirac electron, the exotic surface state of the ETI cannot be regularized in purely two dimensions. Here we introduce the exceptional topological insulator (ETI) realizing a surface anomaly - akin to the three-dimensional topological insulator - that can only exist within the topological bulk embedding. ![]() Non-Hermiticity does not only give rise to new bandstructure features such as point gaps or exceptional points but also enriches the world of topological phases. One of the reasons is that most experimental platforms are in fact either accidentally or tuneably lossy, such that their effective description involves a non-Hermitian Hamiltonian. Our very own Regina Fotler has recieved a prize for the best biogenic toxin poster award (Biogene Toxine Preis der Zeitschrift "Toxins" des MDPI Verlags) titled: Machine Learning Prediction of Cyanobacterial Toxin (Microcystin) Toxicodynamics in Humans at the DGPT conference held this March.Following the success of topological phases in solid-state systems, non-Hermitian physics has recently attracted a lot of interest. Professor Dietrich has recently given an interview for the SRF (Schweizer Radio und Fernsehen) regarding TFA risk in Swiss drinking water, more info can be found here: Professor Dietrich has worked on setting up a website with the goal of providing short and long term relief for refugees from Ukraine around Lake Constance, more info can be found here: “Physiological oxygen and co-culture with human fibroblasts facilitate in vivo-like properties in human renal proximal tubular epithelial cells.” Chemico-biological interactions, 109959.
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