Ein Armutszeugnis für die deutsche Tourismuswirtschaft

Die Unterzeichnung einer über 13 Jahre alten, nicht bindenden Absichtserklärung ist eigentlich kaum eine Meldung wert. Dass der Deutsche Reiseverband (DRV) dies als großes Ereignis feiert, ist eher ein Armutszeugnis für den Stellenwert der Nachhaltigkeit in der deutschen Tourismuswirtschaft

Electronic band structure changes across the antiferromagnetic phase transition of exfoliated MnPS3_3 probed by μ\mu-ARPES

Exfoliated magnetic 2D materials enable versatile tuning of magnetization, e.g., by gating or providing proximity-induced exchange interaction. However, their electronic band structure after exfoliation has not been probed, most likely due to their photochemical sensitivity. Here, we provide micron-scale angle-resolved photoelectron spectroscopy of the exfoliated intralayer antiferromagnet MnPS$_3$ above and below the N\'{e}el temperature down to one monolayer. The favorable comparison with density functional theory calculations enables to identify the orbital character of the observed bands. Consistently, we find pronounced changes across the N\'{e}el temperature for bands that consist of Mn 3d and 3p levels of adjacent S atoms. The deduced orbital mixture indicates that the superexchange is relevant for the magnetic interaction. There are only minor changes between monolayer and thicker films demonstrating the predominant 2D character of MnPS$_3$. The novel access is transferable to other MPX$_3$ materials (M: transition metal, P: phosphorus, X: chalcogenide) providing a multitude of antiferromagnetic arrangements.Comment: 26 pages, 17 figure

Raman imaging of twist angle variations in twisted bilayer graphene at intermediate angles

Van der Waals layered materials with well-defined twist angles between the crystal lattices of individual layers have attracted increasing attention due to the emergence of unexpected material properties. As many properties critically depend on the exact twist angle and its spatial homogeneity, there is a need for a fast and non-invasive characterization technique of the local twist angle, to be applied preferably right after stacking. We demonstrate that confocal Raman spectroscopy can be utilized to spatially map the twist angle in stacked bilayer graphene for angles between 6.5 and 8 degree when using a green excitation laser. The twist angles can directly be extracted from the moiré superlattice-activated Raman scattering process of the transverse acoustic (TA) phonon mode. Furthermore, we show that the width of the TA Raman peak contains valuable information on spatial twist angle variations on length scales below the laser spot size of ∼500 nm

Tourismus als Handlungsfeld der deutschen Entwicklungszusammenarbeit

TOURISMUS ALS HANDLUNGSFELD DER DEUTSCHEN ENTWICKLUNGSZUSAMMENARBEIT Tourismus als Handlungsfeld der deutschen Entwicklungszusammenarbeit / Beyer, Matthias (Rights reserved) ( -

Voluntary carbon offsetting schemes for aviation : efficiency and dredibility

International audienc