Simulating high-pressure surface reactions with molecular beams.

Using a reactive molecular beam with high kinetic energy (), it is possible to speed gas-surface reactions involving high activation barriers (), which would require elevated pressures () if a random gas with a Maxwell-Boltzmann distribution is used. By simply computing the number of molecules that overcome the activation barrier in a random gas at and in a molecular beam at = , we establish an - equivalence curve, through which we postulate that molecular beams are ideal tools to investigate gas-surface reactions that involve high activation energies. In particular, we foresee the use of molecular beams to simulate gas surface reactions within the industrial-range (>10 bar) using surface-sensitive ultra-high vacuum (UHV) techniques, such as X-ray photoemission spectroscopy (XPS).

Insight into the electronic structure of the centrosymmetric skyrmion magnet GdRuSi.

The discovery of a square magnetic-skyrmion lattice in GdRuSi, with the smallest so far found skyrmion size and without a geometrically frustrated lattice, has attracted significant attention. In this work, we present a comprehensive study of surface and bulk electronic structures of GdRuSi by utilizing momentum-resolved photoemission (ARPES) measurements and first-principles calculations. We show how the electronic structure evolves during the antiferromagnetic transition when a peculiar helical order of 4f magnetic moments within the Gd layers sets in.

Long-lived spin waves in a metallic antiferromagnet.

Collective spin excitations in magnetically ordered crystals, called magnons or spin waves, can serve as carriers in novel spintronic devices with ultralow energy consumption. The generation of well-detectable spin flows requires long lifetimes of high-frequency magnons. In general, the lifetime of spin waves in a metal is substantially reduced due to a strong coupling of magnons to the Stoner continuum.

Insight into the Temperature-Dependent Canting of 4f Magnetic Moments from 4f Photoemission.

The orientation of the 4f moments offers an additional degree of freedom for engineering the spin-related properties in spintronic nanostructures of lanthanides. Yet, precise monitoring of the direction of magnetic moments remains a challenge. Here, on the example of the antiferromagnets HoRhSi and DyRhSi, we investigate the temperature-dependent canting of the 4f moments near the surface.