How water binds to microcline feldspar (001)

Microcline feldspar (KAlSi$_3$O$_8$) is a common mineral with important roles for Earth's ecological balance. It participates in the carbon, potassium, and water cycles, contributing to CO$_2$ sequestration, soil formation, and atmospheric ice nucleation. To understand the fundamentals of these processes, it is essential to establish microcline's surface atomic structure and its interaction with the omnipresent water molecules. This work presents atomic-scale results on microcline's lowest-energy surface and its interaction with water, combining ultrahigh vacuum investigations by non-contact atomic force microscopy and X-ray photoelectron spectroscopy with density functional theory calculations. An ordered array of hydroxyls bonded to silicon or aluminum readily forms on the cleaved surface at room temperature. The distinct proton affinities of these hydroxyls influence the arrangement and orientation of the first water molecules binding to the surface, holding potential implications for the subsequent condensation of water.Comment: 14 pages, 5 figure

Single-domain h-BN on Pt(110): Electronic structure, correlation, and bonding

Extended single-domain growth of h-BN is observed on Pt(110), if the precursor molecules are deposited at sufficiently high temperatures. We examined the electronic structure of the h-BN/Pt(110) system by angle-resolved photoemission (ARPES), work-function measurements, and density-functional theory (DFT) calculations. van der Waals forces dominate the h-BN/Pt(110) interaction by far, although DFT analysis of the local density of states reveals the existence of a local covalent interaction of some N atoms with Pt surface atoms. The local bonding contributions cause the appearance of a (1×n) missing-row reconstruction (n=5 or 6) of the Pt (110) surface, if the system reverts to room temperature after h-BN adlayer formation at 1120 K. This unique phenomenon of the template adapting to the adlayer structure mitigates differences in the thermal-expansion coefficient upon cooling. The h-BN π bands hybridize with Pt d bands. Nevertheless, the dispersion of π and σ bands as measured by ARPES is overall well represented by the free-standing monolayer band structure except for the appearance of replica bands induced by the Moiré structure. A comparison between the experimentally measured π bands and the band structure obtained from DFT slab calculations suggest the existence of significant correlation effects in photoemission from h-BN/Pt(110). The locally varying distribution of N-Pt hybrid states straddling the Fermi level indicates a corresponding spatial variation of the chemical reactivity

Many-electron calculations of the phase stability of ZrO_{2} polymorphs

Zirconia (ZrO_{2}) has been well studied experimentally for decades, but still poses a severe challenge for computational approaches. We present thorough many-electron benchmark calculations within the random-phase approximation framework of the phase stabilities of the most common ZrO_{2} phases and assess the performance of various density functional theory (DFT) and beyond-DFT methods. We find that the commonly used DFT and hybrid functionals strongly overestimate both the energetic differences of the common phases and the stability of two metastable phases. The many-electron calculations offer a significantly improved description of the predicted bulk properties, especially of the bulk modulus B_{0}. On the DFT level, the van der Waals corrected meta-generalized-gradient approximation (SCAN-rVV10) provides much better agreement with the experimental values than other (semi)local and hybrid approaches