Mott scattering at the interface between a metal and a topological insulator

We compute the spin-active scattering matrix and the local spectrum at the interface between a metal and a three-dimensional topological band insulator. We show that there exists a critical incident angle at which complete (100%) spin flip reflection occurs and the spin rotation angle jumps by $\pi$. We discuss the origin of this phenomena, and systematically study the dependence of spin-flip and spin-conserving scattering amplitudes on the interface transparency and metal Fermi surface parameters. The interface spectrum contains a well-defined Dirac cone in the tunneling limit, and smoothly evolves into a continuum of metal induced gap states for good contacts. We also investigate the complex band structure of Bi$_2$Se$_3$.Comment: published versio

Body adiposity index and incident hypertension: The Aerobics Center Longitudinal Study

Background and aim The body adiposity index (BAI) has been recently proposed as a new method to estimate the percentage of body fat. The association between BAI and hypertension risk has not been investigated yet. The aim of our study was to evaluate the ability of BAI to predict hypertension in males and females compared with traditional body adiposity measures. Methods and results The present follow-up analysis comprised 10,309 individuals (2259 females) free of hypertension from the Aerobics Center Longitudinal Study, who completed a baseline examination between 1988 and 2003. Body adiposity measures included BAI, body mass index (BMI), waist circumference, hip circumference, percentage of body fat and waist to hip ratio (WHR). Incident hypertension was ascertained from responses to mail-back surveys between 1990 and 2004. During an average of 9.1 years of follow-up, 872 subjects (107 females) became hypertensive. Hazard ratios (HRs) and 95% confidence intervals (95% CI) showed that males in the highest categories of all body adiposity measures showed a higher incident risk of hypertension (HRs ranged from 1.37 to 2.09). Females showed a higher incident risk of hypertension only in the highest categories of BAI, BMI and WHR (HRs ranged from 1.84 to 3.36). Conclusion Our results suggest that in order to predict incident hypertension BAI could be considered as an alternative to traditional body adiposity measures.The authors thank the Cooper Clinic physicians and technicians for collecting the data, and staff at the Cooper Institute for data entry and data management. This work was supported by “Conselleria de Educación de la Generalitat Valenciana” [BEST/2012/257]; Spanish Ministry of Education [EX-2010-1008]; National Institutes of Health [AG06945, HL62508, R21DK088195] and in part by an unrestricted research grant from The Coca-Cola Company. The content is solely the responsibility of the authors and does not necessarily represent the official views of the funding institutions

The translationally-invariant coupled cluster method in coordinate space

We study a formulation of the translationally-invariant coupled cluster method in coordinate space. Previous calculations in configuration space showed poor convergence, a problem that the new formulation is expected to remedy. This question is investigated for a system of bosons interacting through the Wigner part of the Afnan-Tang S3 interaction, where previous results exist.Facultad de Ciencias Exacta

On the Origin of the -4.4 eV Band in CdTe(100)"

We calculate the bulk- (infinite system), (100)-bulk-projected- and (100)-Surface-projected Green's functions using the Surface Green's Function Matching method (SGFM) and an empirical tight-binding hamiltonian with tight-binding parameters (TBP) that describe well the bulk band structure of CdTe. In particular, we analyze the band (B--4) arising at --4.4 eV from the top of the valence band at $\Gamma$ according to the results of Niles and H\"ochst and at -4.6 eV according to Gawlik {\it et al.} both obtained by Angle-resolved photoelectron spectroscopy (ARPES). We give the first theoretical description of this band.Comment: 17 pages, Rev-TEX, CIEA-Phys. 02/9

Wired metal-organic chalcogenides

Rey Garcia, F.; Jorda Moret, JL. (2017). Bottom-up synthesis: Wired metal-organic chalcogenides. Nature Materials. 16(3):287-288. doi:10.1038/nmat4850S287288163Moliner, M., Rey, F. & Corma, A. Angew. Chem. Int. Ed. 52, 13880–13889 (2013).Zeolites and Catalysis: Synthesis, Reactions and Applications Vol. 2 (eds Cejka, J., Corma, A. & Zones, S. I.) 389–861 (Wiley, 2010).Furukawa, H., Cordova, K. E., O'Keeffe, M. & Yaghi, O. M. Science 341, 1230444 (2013).Yan, H. et al. Nat. Mater. 16, 349–355 (2017).Bedard, R. L., Vail, L. D., Wilson, S. T., Oak, S. & Flanigen, E. M. US patent 4,880,761 (1989).Bowes, C. L. et al. Chem. Mater. 8, 2147–2152 (1996).MacLachlan, M. J. et al. J. Am. Chem. Soc. 121, 12005–12017 (1999).Zheng, N., Bu, X., Wang, B. & Feng, P. Science 298, 2366–2369 (2002).Dance, I. G., Garbutt, R. G. & Scudder, M. L. Inorg. Chem. 29, 1571–1575 (1990).Dance, I. G., Garbutt, R. G., Craig, D. C. & Scudder, M. L. Inorg. Chem. 26, 4057–4064 (1987)

Surface plasmons at composite surfaces with diffusive charges

Metal surfaces with disorder or with nanostructure modifications are studied, allowing for a localized charge layer (CL) in addition to continuous charges (CC) in the bulk, both charges having a compressional or diffusive non-local response. The notorious problem of "additional boundary conditions" is resolved with the help of a Boltzmann equation that involves the scattering between the two charge types. Depending on the strength of this scattering, the oscillating charges can be dominantly CC or CL; the surface plasmon (SP) resonance acquires then a relatively small linewidth, in agreement with a large set of data. With a few parameters our model describes a large variety of SP dispersions corresponding to observed data.Comment: 6 pages, 2 figure

NH3-SCR catalysts for heavy-duty diesel vehicles: Preparation of CHA-type zeolites with low-cost templates

Computer-assistance allows selecting the most adequate low-cost organic structure directing agents (OSDAs) for the crystallization of Al-rich CHA-type zeolites. The host-guest stabilization energies of tetraethylammonium (TEA), methyltriethylammonium (MTEA) and dimethyldiethylammonium (DMDEA), in combination with Na, were first theoretically evaluated. This “ab-initio” analysis reveals that two TEA show a serious steric hindrance in a cha cavity, whereas two MTEA would present excellent host-guest confinements. The synthesis of Al-rich CHA-type zeolites has been accomplished using TEA and MTEA. Electron diffraction and high-resolution transmission electron microscopy reveal large CHA-domains with narrow faulted GME-domains in the CHA-type material synthesized with TEA, confirming the better OSDA-directing roles of MTEA cations towards the cha cavity, in good agreement with DFT calculations. Cu-exchanged Al-rich CHA-type samples achieved with MTEA and TEA show excellent catalytic activity and hydrothermal stability for the selective catalytic reduction (SCR) of NOx with ammonia under conditions relevant for future heavy duty diesel conditions.This work has been supported by Umicore and by the Spanish Government-MCIU through RTI2018-101033-B-I00 (MCIU/AEI/FEDER, UE) and PID2020-112590GB-C21 (AEI/FEDER, UE). T.W. acknowledges financial support by the Swedish Research Council (Grant No. 2019-05465). E.B. acknowledges the Spanish Government-MCIU for a FPI scholarship (PRE2019-088360). P.F. thanks ITQ for a contract. The Electron Microscopy Service of the UPV is acknowledged for their help in sample characterization. The computations were performed on the Tirant III cluster of the Servei d'Informàtica of the University of Valencia

High-Order Coupled Cluster Method Study of Frustrated and Unfrustrated Quantum Magnets in External Magnetic Fields

We apply the coupled cluster method (CCM) in order to study the ground-state properties of the (unfrustrated) square-lattice and (frustrated) triangular-lattice spin-half Heisenberg antiferromagnets in the presence of external magnetic fields. Here we determine and solve the basic CCM equations by using the localised approximation scheme commonly referred to as the `LSUB$m$' approximation scheme and we carry out high-order calculations by using intensive computational methods. We calculate the ground-state energy, the uniform susceptibility, the total (lattice) magnetisation and the local (sublattice) magnetisations as a function of the magnetic field strength. Our results for the lattice magnetisation of the square-lattice case compare well to those results of QMC for all values of the applied external magnetic field. We find a value for magnetic susceptibility of $\chi=0.070$ for the square-lattice antiferromagnet, which is also in agreement with the results of other approximate methods (e.g., $\chi=0.0669$ via QMC). Our estimate for the range of the extent of the ($M/M_s=$)$\frac 13$ magnetisation plateau for the triangular-lattice antiferromagnet is $1.37< \lambda < 2.15$, which is in good agreement with results of spin-wave theory ($1.248 < \lambda < 2.145$) and exact diagonalisations ($1.38 < \lambda < 2.16$). The CCM value for the in-plane magnetic susceptibility per site is $\chi=0.065$, which is below the result of the spin-wave theory (evaluated to order 1/S) of $\chi_{SWT}=0.0794$.Comment: 30 pages, 13 figures, 1 Tabl