Electron dephasing in homogeneous and inhomogeneous indium tin oxide thin films

The electron dephasing processes in two-dimensional homogeneous and inhomogeneous indium tin oxide thin films have been investigated in a wide temperature range 0.3--90 K. We found that the small-energy-transfer electron-electron ($e$-$e$) scattering process dominated the dephasing from a few K to several tens K. At higher temperatures, a crossover to the large-energy-transfer $e$-$e$ scattering process was observed. Below about 1--2 K, the dephasing time $\tau_\varphi$ revealed a very weak temperature dependence, which intriguingly scaled approximately with the inverse of the electron diffusion constant $D$, i.e., $\tau_\varphi (T \approx 0.3 \, {\rm K}) \propto 1/D$. Theoretical implications of our results are discussed. The reason why the electron-phonon relaxation rate is negligibly weak in this low-carrier-concentration material is presented.Comment: 10 pages, 7 figure

Geochronology and Tectonic Significance of Middle Proterozoic Granitic Orthogneiss, North Qaidam HP/UHP Terrane, Western China

Amphibolite-facies para- and orthogneisses near Dulan, in the southeast part of the North Qaidam terrane, enclose minor ultra-high pressure (UHP) eclogite and peridotite. Field relations and coesite inclusions in zircons from paragneiss suggest that felsic, mafic, and ultramafic rocks all experienced UHP metamorphism and a common amphibolite-facies retrogression. Ion microprobe U–Pb and REE analyses of zircons from two granitic orthogneisses indicate magmatic crystallization at 927 ± Ma and 921 ± 7 Ma. Zircon rims in one of these samples yield younger ages (397–618 Ma) compatible with partial zircon recrystallization during in-situ Ordovician-Silurian eclogite-facies metamorphism previously determined from eclogite and paragneiss in this area. The similarity between a 2496 ± 18 Ma xenocrystic core and 2.4–2.5 Ga zircon cores in the surrounding paragneiss suggests that the granites intruded the sediments or that the granite is a melt of the older basement which supplied detritus to the sediments. The magmatic ages of the granitic orthogneisses are similar to 920–930 Ma ages of (meta)granitoids described further northwest in the North Qaidam terrane and its correlative west of the Altyn Tagh fault, suggesting that these areas formed a coherent block prior to widespread Mid Proterozoic granitic magmatism. Included here is the post-print copy of this article. The final publication is available at Springer via http://dx.doi.org/10.1007/s00710-006-0149-1

Thermodynamic properties and structural stability of thorium dioxide

Using density functional theory (DFT) calculations, we have systematically investigated the thermodynamic properties and structural stabilities of thorium dioxide (ThO$_2$). Based on the calculated phonon dispersion curves, we calculate the thermal expansion coefficient, bulk modulus, and heat capacities at different temperatures for ThO$_2$ under the quasi-harmonic approximation. All the results are in good agreement with corresponding experiments proving the validity of our methods. Our theoretical studies can help people more clearly understand the thermodynamic behaviors of ThO$_2$ at different temperatures. In addition, we have also studied possible defect formations and diffusion behaviors of helium in ThO$_2$, to discuss its structural stability. It is found that in intrinsic ThO$_2$ without any Fermi energy shifts, the interstitial Th$_i^{4+}$ defect other than oxygen or thorium vacancies, interstitial oxygen, and any kinds of Frenkel pairs, is most probable to form with an energy release of 1.74 eV. However, after upshifting the Fermi energy, the formation of the other defects also becomes possible. For helium diffusion, we find that only through the thorium vacancy can it happen with the small energy barrier of 0.52 eV. Otherwise, helium atoms can hardly incorporate or diffuse in ThO$_2$. Our results indicate that people should prevent upshifts of the Fermi energy of ThO$_2$ to avoid the formation of thorium vacancies and so as to prevent helium caused damages.Comment: 11 pages, 11 figure

Homeownership and Wealth in Switzerland and Germany

Property wealth represents the most important wealth component in nearly all OECD countries. Homeownership is linked to wealth accumulation in several ways: Wealthier households are more likely to buy a house or apartment, home owners tend to save more and rising house values typically yield higher returns than money in a bank account. Moreover, owners can borrow on a mortgage to finance, e.g., the formation of an enterprise or other economic activities. At the aggregate level, these relations can explain why countries with low rates of homeownership tend to have a high wealth inequality. This paper looks at wealth and homeownership in Germany and Switzerland. These countries show the lowest proportion of owner-occupiers in Europe and a high wealth inequality. We analyse to what extent this high inequality can be explained by homeownership status. In the first part of this contribution, we review explanations for the low share of owner-occupiers in the two countries. In the second part, we analyse wealth and homeownership empirically using data of the SHP and the German Socio-Economic Panel (SOEP) from 2012. We make use of decomposition methods to analyse how renter and owner households differ in wealth levels and wealth inequality

Two-Channel Kondo Effects in Al/AlOx_{x}/Sc Planar Tunnel Junctions

We have measured the differential conductances $G(V,T)$ in several Al/AlO$_{x}$/Sc planar tunnel junctions between 2 and 35 K. As the temperature decreases to $\sim$ 16 K, the zero-bias conductance $G(0,T)$ crosses over from a standard $-$ln$T$ dependence to a novel $- \sqrt{T}$ dependence. Correspondingly, the finite bias conductance $G(V,T)$ reveals a two-channel Kondo scaling behavior between $\sim$ 4 and 16 K. The observed two-channel Kondo physics is ascribed to originating from a few localized spin-$\frac12$ Sc atoms situated slightly inside the AlO$_x$/Sc interface.Comment: 4 pages, 3 figures. Phys. Rev. B (accepted

Beyond the mean gender wage gap : decomposition of differences in wage distributions using quantile regression

Using linked employer-employee data, this study measures and decomposes the differences in the earnings distribution between male and female employees in Germany. I extend the traditional decomposition to disentangle the effect of human capital characteristics and the effect of firm characteristics in explaining the gender wage gap. Furthermore, I implement the decomposition across the whole wage distribution with the method proposed by Machado and Mata (2005). Thereby, I take into account the dependence between the human capital endowment of individuals and workplace characteristics. The selection of women into less successful and productive firms explains a sizeable part of the gap. This selection is more pronounced in the lower part of the wage distribution than in the upper tail. In addition, women also benefit from the success of firms by rent-sharing to a lesser extent than their male colleagues. This is the source of the largest part of the pay gap. Gender differences in human capital endowment as well s differences in returns to human capital are less responsible for the wage differential

Timing of eclogite-facies metamorphism of the Chuacús complex, Central Guatemala: Record of Late Cretaceous continental subduction of North America's sialic basement

A Late Cretaceous collision of the southernmost portion of the North American continental margin with an undetermined southern block was first established based on the sedimentation history of the plate's supracrustal cover, which is overthrust by harzburgite-dominated nappes of the Guatemala Suture Complex. The collision is also well registered in the metamorphic evolution of continental eclogites of the Chuacús complex, a geologic unit that represents Mesoproterozoic–Triassic sialic basement of North America at the boundary with the Caribbean plate. Garnet–clinopyroxene–phengite thermobarometry of eclogites hosted in Chuacús gneisses indicates near ultra-high-pressure conditions to ~ 700 °C and ~ 2.1–2.4 GPa. SHRIMP-RG U–Pb dating of eclogite metamorphic zircon yielded a 75.5 ± 2 Ma age (95% confidence level). Chondrite-normalized rare-earth element patterns of zircon lack Eu anomalies and show depletions in heavy rare earths, consistent with zircon growing in a plagioclase-free, garnet-rich, eclogite-facies assemblage. Additionally, a Sm–Nd clinopyroxene-two garnet–whole rock isochron from an eclogite band yielded a less precise but consistent age of 77 ± 13 Ma. The above features imply subduction to > 60 km depth of at least a portion of the North American sialic basement during Late Cretaceous collision. The Chuacús complex was overprinted by an amphibolite-facies event. For instance, mafic high-pressure paragneiss contains symplectite, resorbed garnet, and amphibole + plagioclase poikiloblasts. Zircon rims from the paragneiss sample show rare-earth patterns consistent with plagioclase growth and garnet breakdown. Their 74.5 ± 3.5 Ma SHRIMP-RG U–Pb age is therefore interpreted as the time of retrogression, which is consistent with previously published results. Within error, the ages of the eclogite-facies event and the amphibolite-facies retrogression are equivalent. Thus exhumation of the Chuacús slab from mantle to mid-crustal depth was quick, taking few million years. During exhumation, partial melting of Chuacús gneisses generated ubiquitous pegmatites. One of the pegmatites intruded the North Motagua mélange, which is a serpentinite-rich subduction complex of the Guatemala Suture Complex containing Early Cretaceous oceanic eclogites. U–Pb, Rb–Sr, and K–Ar ages of the pegmatite range ~ 76–66 Ma. Thus initial juxtaposition of continental and oceanic high-pressure belts of the Guatemala Suture Complex predates Tertiary–present strike-slip faulting between the North-American and Caribbean plates

Topography-driven isolation, speciation and a global increase of endemism with elevation

Aim: Higher-elevation areas on islands and continental mountains tend to be separated by longer distances, predicting higher endemism at higher elevations; our study is the first to test the generality of the predicted pattern. We also compare it empirically with contrasting expectations from hypotheses invoking higher speciation with area, temperature and species richness. Location: Thirty-two insular and 18 continental elevational gradients from around the world. Methods: We compiled entire floras with elevation-specific occurrence information, and calculated the proportion of native species that are endemic (‘percent endemism’) in 100-m bands, for each of the 50 elevational gradients. Using generalized linear models, we tested the relationships between percent endemism and elevation, isolation, temperature, area and species richness. Results: Percent endemism consistently increased monotonically with elevation, globally. This was independent of richness–elevation relationships, which had varying shapes but decreased with elevation at high elevations. The endemism–elevation relationships were consistent with isolation-related predictions, but inconsistent with hypotheses related to area, richness and temperature. Main conclusions: Higher per-species speciation rates caused by increasing isolation with elevation are the most plausible and parsimonious explanation for the globally consistent pattern of higher endemism at higher elevations that we identify. We suggest that topography-driven isolation increases speciation rates in mountainous areas, across all elevations and increasingly towards the equator. If so, it represents a mechanism that may contribute to generating latitudinal diversity gradients in a way that is consistent with both present-day and palaeontological evidence

Measurement of inner wall limiter SOL widths in KSTAR tokamak

https://doi.org/10.1016/j.nme.2016.12.001.Scrape-off layer (SOL) widths λq are presented from the KSTAR tokamak using fast reciprocating Langmuir probe assembly (FRLPA) measurements at the outboard mid-plane (OMP) and the infra-Red (IR) thermography at inboard limiter tiles in moderately elongated (κ = 1.45 – 1.55) L-mode inner wall-limited (IWL) plasmas under experimental conditions such as BT = 2.0 T, PNBI = 1.4 – 1.5 MW, line averaged densities 2.5 – 5.1 × 1019 m−3) and plasma current Ip = 0.4 − 0.7 MA. There is clear evidence for a double exponential structure in q||(r) from the FRLPA such that, for example at Ip = 0.6 MA, a narrow feature, λq,near (=3.5 mm) is found close to the LFCS, followed by a broader width, λq,main (=57.0 mm). Double exponential profiles (λq,near = 1.5 – 2.8 mm, λq,main = 17.0 – 35.0 mm) can be also observed in the IR heat flux mapped to the OMP throughout the range of Ip investigated. In addition, analysis of SOL turbulence statistics obtained with the FRLPA shows high relative fluctuation levels and positively skewed distributions in electron temperature and ion particle flux across the SOL, with both properties increasing for longer distance from the LCFS, as often previously observed in the tokamaks. Interestingly, the fluctuation character expressed in terms of spectral distributions remains unchanged in passing from the narrow to the broad SOL heat flux channel