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

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.

Achieving environmental stability in an atomically thin quantum spin Hall insulator via graphene intercalation.

Atomic 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.

Co-learning and co-teaching in a newly introduced research learning community.

Background: Research clerkships are usually designed as individual learning projects focusing on research skills training, such as research design, data analysis and reporting. When the COVID-19 pandemic triggered an urgent need for digital education, we redesigned a research clerkship with the challenging aim to maintain original quality for more students than usual with limited teaching staff.

Approach: We introduced the concept of a research learning community (RLC) with co-teaching and co-learning to a group of 14 students and seven teaching faculty using digital platforms.

How to coach student professional development during times of challenges and uncertainties.

Background: What we teach our (bio)medical students today may differ from the future context under which they will operate as health professionals. This shifting and highly demanding profession requires that we equip these students with adaptive competencies for their future careers. We aimed to develop a framework to promote and facilitate professional development from day one, guided by self-awareness and self-directed learning.

Moiré Pattern Formation in Epitaxial Growth on a Covalent Substrate: Sb on InSb(111)A.

Structural 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.

The teacher as coach: An innovative, longitudinal training for (bio)medical educators.

Background: In order to be impactful, to support students to become resilient, adaptive, and collaborative lifelong learning professionals in an ever-changing environment requires the teachers to have a specific set of skills and abilities. Teachers who are not taught these competencies struggle empirically and cannot coach students effectively in the modern professional world.

Approach: We developed a longitudinal programme for teachers, combining theory and skills training, and performed nine half-day hands-on training modules on campus.

Observation of room temperature excitons in an atomically thin topological insulator.

Optical spectroscopy of ultimately thin materials has significantly enhanced our understanding of collective excitations in low-dimensional semiconductors. This is particularly reflected by the rich physics of excitons in atomically thin crystals which uniquely arises from the interplay of strong Coulomb correlation, spin-orbit coupling (SOC), and lattice geometry. Here we extend the field by reporting the observation of room temperature excitons in a material of non-trivial global topology.

Effective lifting of the topological protection of quantum spin Hall edge states by edge coupling.

The scientific interest in two-dimensional topological insulators (2D TIs) is currently shifting from a more fundamental perspective to the exploration and design of novel functionalities. Key concepts for the use of 2D TIs in spintronics are based on the topological protection and spin-momentum locking of their helical edge states. In this study we present experimental evidence that topological protection can be (partially) lifted by pairwise coupling of 2D TI edges in close proximity.

Ultrafast Momentum-Resolved Hot Electron Dynamics in the Two-Dimensional Topological Insulator Bismuthene.

Two-dimensional quantum spin Hall (QSH) insulators are a promising material class for spintronic applications based on topologically protected spin currents in their edges. Yet, they have not lived up to their technological potential, as experimental realizations are scarce and limited to cryogenic temperatures. These constraints have also severely restricted characterization of their dynamical properties.

Implant survival after graftless sinus floor augmentation in highly atrophic maxillae: a randomized controlled trial in a split mouth study.

Purpose: The success rate of dental implants after graftless sinus augmentation versus conventional sinus augmentation surgery in atrophic maxillae in edentulous patients was investigated.

Methods: This randomized study was performed in ten edentulous patients with marked maxillary atrophy. On the graftless side, the sinus membrane was lifted by a resorbable membrane.

Non-grafted versus grafted sinus lift procedures for implantation in the atrophic maxilla: a systematic review and meta-analysis of randomized controlled trials.

The aim of this systematic review and meta-analysis was to critically evaluate the currently existing clinical evidence on the efficacy of graftless maxillary sinus membrane elevation for implantation in the atrophic posterior maxilla. A search protocol without limitations to November 2020 was followed by two independent researchers. Randomized controlled trials using the lateral window approach for graftless sinus membrane elevation were included.

[PCSK9 inhibitors; who benefits from these new cholesterol-lowering drugs?].

PCSK9 inhibitors are monoclonal antibodies that target the protein PCSK9. These drugs (alirocumab and evolcumab) are a new generation of cholesterol-lowering agents for patients with a very high risk of cardiovascular disease. They lower the LDL cholesterol concentration by approximately 50% in comparison with placebo, thereby lowering the risk of myocardial infarction, stroke and cardiovascular death in high-risk patients.

Correlation-Driven Charge Order in a Frustrated Two-Dimensional Atom Lattice.

We thoroughly examine the ground state of the triangular lattice of Pb on Si(111) using scanning tunneling microscopy and spectroscopy. We detect electronic charge order, and disentangle this contribution from the atomic configuration which we find to be 1-down-2-up, contrary to previous predictions from density functional theory. Applying an extended variational cluster approach we map out the phase diagram as a function of local and nonlocal Coulomb interactions.

A Living-Dead Magnetic Layer at the Surface of Ferrimagnetic DyTiO Thin Films.

When ferromagnetic films become ultrathin, key properties such as the Curie temperature and the saturation magnetization are usually depressed. This effect is thoroughly investigated in magnetic oxides such as half-metallic manganites, but much less in ferrimagnetic insulating perovskites such as rare-earth titanates RTiO , despite their appeal to design correlated 2D electron gases. Here, the magnetic properties of epitaxial DyTiO thin films are reported.

Controlling the Local Electronic Properties of Si(553)-Au through Hydrogen Doping.

We propose a quantitative and reversible method for tuning the charge localization of Au-stabilized stepped Si surfaces by site-specific hydrogenation. This is demonstrated for Si(553)-Au as a model system by combining density functional theory simulations and reflectance anisotropy spectroscopy experiments. We find that controlled H passivation is a two-step process: step-edge adsorption drives excess charge into the conducting metal chain "reservoir" and renders it insulating, while surplus H recovers metallic behavior.

Tailoring Materials for Mottronics: Excess Oxygen Doping of a Prototypical Mott Insulator.

The Mott transistor is a paradigm for a new class of electronic devices-often referred to by the term Mottronics-which are based on charge correlations between the electrons. Since correlation-induced insulating phases of most oxide compounds are usually very robust, new methods have to be developed to push such materials right to the boundary to the metallic phase in order to enable the metal-insulator transition to be switched by electric gating. Here, it is demonstrated that thin films of the prototypical Mott insulator LaTiO grown by pulsed laser deposition under oxygen atmosphere are readily tuned by excess oxygen doping across the line of the band-filling controlled Mott transition in the electronic phase diagram.

Dimensionality-Driven Metal-Insulator Transition in Spin-Orbit-Coupled SrIrO_{3}.

Upon reduction of the film thickness we observe a metal-insulator transition in epitaxially stabilized, spin-orbit-coupled SrIrO_{3} ultrathin films. By comparison of the experimental electronic dispersions with density functional theory at various levels of complexity we identify the leading microscopic mechanisms, i.e.

One-dimensional quantum matter: gold-induced nanowires on semiconductor surfaces.

Interacting electrons confined to only one spatial dimension display a wide range of unusual many-body quantum phenomena, ranging from Peierls instabilities to the breakdown of the canonical Fermi liquid paradigm to even unusual spin phenomena. The underlying physics is not only of tremendous fundamental interest, but may also have bearing on device functionality in future micro- and nanoelectronics with lateral extensions reaching the atomic limit. Metallic adatoms deposited on semiconductor surfaces may form self-assembled atomic nanowires, thus representing highly interesting and well-controlled solid-state realizations of such 1D quantum systems.

Bismuthene on a SiC substrate: A candidate for a high-temperature quantum spin Hall material.

Quantum spin Hall materials hold the promise of revolutionary devices with dissipationless spin currents but have required cryogenic temperatures owing to small energy gaps. Here we show theoretically that a room-temperature regime with a large energy gap may be achievable within a paradigm that exploits the atomic spin-orbit coupling. The concept is based on a substrate-supported monolayer of a high-atomic number element and is experimentally realized as a bismuth honeycomb lattice on top of the insulating silicon carbide substrate SiC(0001).

Poor anticoagulation relates to extended access times for cardioversion and is associated with long-term major cardiac and cerebrovascular events.

Background: Patients undergoing elective electrical cardioversion (ECV) for atrial fibrillation have a temporarily increased risk of thromboembolism. Current guidelines recommend adequate anticoagulation for ≥3 consecutive weeks precardioversion, i.e.

In Situ Control of Separate Electronic Phases on SrTiO3 Surfaces by Oxygen Dosing.

Insulating SrTiO3 (STO) can host 2D electron systems (2DESs) on its surfaces, caused by oxygen defects. This study shows that the STO surface exhibits phase separation once the 2DES is formed and relates this inhomogeneity to recently reported magnetic order at STO surfaces and interfaces. The results open pathways to exploit oxygen defects for engineering the electronic and magnetic properties of oxides.

Two-Dimensional, but not Flat: An All-Boron Graphene with a Corrugated Structure.

The construction of single-atom-thick sheets of boron on a silver substrate, which was published in late 2015, represents a significant advance towards the realization of useful two-dimensional materials based solely on boron. This Highlight provides background information on the topic of boron allotropes and an outlook for further work in this area.

Spin Chains and Electron Transfer at Stepped Silicon Surfaces.

High-index surfaces of silicon with adsorbed gold can reconstruct to form highly ordered linear step arrays. These steps take the form of a narrow strip of graphitic silicon. In some cases--specifically, for Si(553)-Au and Si(557)-Au--a large fraction of the silicon atoms at the exposed edge of this strip are known to be spin-polarized and charge-ordered along the edge.