The polarization vector of the Rashba spin, which must be parallel to the two-dimensional (2D) plane in an ideal system, is found to change abruptly and definitely to the direction perpendicular to the surface at the K̅ point of the Brillouin zone of a real hexagonal system, the Tl/Si(111)-(1×1) surface. This finding obtained experimentally by angle-resolved and spin-resolved photoemission measurements is fully confirmed by a first-principles theoretical calculation. We found that the abrupt rotation of the Rashba spin is simply understood by the 2D symmetry of the hexagonal structure

The chelating gadolinium-complex is routinely used as magnetic resonance imaging (MRI) -contrast enhancer. However, several safety issues have recently been reported by FDA and PRAC. There is an urgent need for the next generation of safer MRI-contrast enhancers, with improved local contrast and targeting capabilities. Cerium oxide nanoparticles (CeNPs) are designed with fractions of up to 50% gadolinium to utilize the superior MRI-contrast properties of gadolinium. CeNPs are well-tolerated in vivo and have redox properties making them suitable for biomedical applications, for example scavenging purposes on the tissue- and cellular level and during tumor treatment to reduce in vivo inflammatory processes. Our near edge X-ray absorption fine structure (NEXAFS) studies show that implementation of gadolinium changes the initial co-existence of oxidation states Ce3+ and Ce4+ of cerium, thereby affecting the scavenging properties of the nanoparticles. Based on ab initio electronic structure calculations, we describe the most prominent spectral features for the respective oxidation states. The as-prepared gadolinium-implemented CeNPs are 3–5 nm in size, have r1-relaxivities between 7–13 mM−1 s−1 and show clear antioxidative properties, all of which means they are promising theranostic agents for use in future biomedical applications.

The aim of this work is to provide a thorough thermal characterization of membrane structures intended for thermal infrared detector arrays. The fabrication has been conducted at temperatures below 400 C to allow future post processing onto existing CMOS readout circuitry. Our choices of membrane material and processing technique were plasma enhanced chemical vapor deposited silicon nitride (SiN) and surface micromachining, respectively. The characterization gave for the thermal conductance (G) and thermal mass between the membrane and its surroundings 1.8 1 10 07 W/K and 1.7 1 10 09 J/K, respectively, which are close to the best reported values elsewhere. From these results the thermal conductivity and specific heat of SiN were extracted as 4.5 6 0.7 W/m.K and 1500 6 230 J/kg.K. The contribution to G from different heat transfer mechanisms are estimated. A model describing the pressure dependence of G was developed and verified experimentally in the pressure interval [5 1 10 03 , 1000] mbar. Finally, the influence of the thermal properties of the membrane on infrared detector performance is discussed. [205]Index Terms-Silicon nitride membranes, surface micromachining.

The electronic structure of a single domain Si͑110͒-͑16ϫ 2͒ surface has been investigated by high-resolution angle-resolved photoelectron spectroscopy and scanning tunneling microscopy ͑STM͒. Four semiconducting surface states with flat dispersions, whose binding energies are 0.2, 0.4, 0.75, and 1.0 eV, were observed in the bulk band gap and more than six states were observed within the projected bulk band at binding energies less than 5.2 eV. The origins of the four surface states and of one state at a binding energy of approximately 1.5 eV at the ⌫ point are discussed based on the local density of states mappings obtained by STM. Further, a structural model that can explain all these five states is proposed.

Surface core-level shifts on clean Si(001) and Ge(001) studied with photoelectron spectroscopy and DFT calculations, 2010, Physical Review B.