Direct Observation of Interband Spin-Orbit Coupling in a Two-Dimensional Electron System

We report the direct observation of interband spin-orbit (SO) coupling in a two-dimensional (2D) surface electron system, in addition to the anticipated Rashba spin splitting. Using angle-resolved photoemission experiments and first-principles calculations on Bi/Ag/Au heterostructures we show that the effect strongly modifies the dispersion as well as the orbital and spin character of the 2D electronic states, thus giving rise to considerable deviations from the Rashba model. The strength of the interband SO coupling is tuned by the thickness of the thin film structures

Comparative study of the electronic structures of the In and Sn/In2O3 (111) interfaces

The electronic structure of the transparent semiconductor In2O3 has been studied by angle resolved photoemission spectroscopy upon deposition of metallic indium and also tin on the surface of the semiconductor. By deposition of metallic indium on In2O3 (111) single crystals, we detected the formation of a free-electron like band of effective mass (0.38+-0.05) m0. At low coverages, metallic In shifts the Fermi level of In2O3 to higher energies and a new electronic state forms at the metal/semiconductor interface. This state of two-dimensional character (2D-electron gas) is completely responsible for the electrical conduction in In2O3 (111) at the surface region and has a band dispersion, which does not correspond to the previously found surface accumulation layers in this material. Despite the similarity of the electronic properties of In and Sn, a larger downward banding was observed by Sn coverage, which was not accompanied by the appearance of the surface state.Comment: 5 pages, 3 figure

Out-of-plane nesting driven spin spiral in ultrathin Fe/Cu(001) films

Epitaxial ultrathin Fe films on fcc Cu(001) exhibit a spin spiral (SS), in contrast to the ferromagnetism of bulk bcc Fe. We study the in-plane and out-of-plane Fermi surfaces (FSs) of the SS in 8 monolayer Fe/Cu(001) films using energy dependent soft x-ray momentum-resolved photoemission spectroscopy. We show that the SS originates in nested regions confined to out-of-plane FSs, which are drastically modified compared to in-plane FSs. From precise reciprocal space maps in successive zones, we obtain the associated real space compressive strain of 1.5+-0.5% along c-axis. An autocorrelation analysis quantifies the incommensurate ordering vector q=(2pi/a)(0,0,~0.86), favoring a SS and consistent with magneto-optic Kerr effect experiments. The results reveal the importance of in-plane and out-of-plane FS mapping for ultrathin films.Comment: 4 pages, 3 figure

Incidencia de la participación en el empoderamiento personal y familiar, el poder de agencia y la autogestión comunitaria de un grupo emprendedor liderado por mujeres

En estos últimos tiempos, en los que la desocupación se ha instalado en nuestra sociedad, muchas mujeres han decidido encarar un emprendimiento para generar, aportar y/ o aumentar los ingresos hogareños, motivadas por diversos motivos pero, especialmente, por la falta de trabajo. En esta ocasión realizamos un estudio de caso de un grupo liderado por mujeres que se dedicó a la producción de alimentos en Tandil. Este trabajo se propone analizar la incidencia de la participación de estas mujeres en dicho emprendimiento en el empoderamiento personal y familiar, el poder de agencia y la autogestión comunitaria. La metodología utilizada se basó en entrevistas semi estructuradas y en profundidad a las mujeres integrantes del grupo y a profesionales técnicos que trabajan con el grupo, como también en recolección de información secundaria

Caracterización de la agricultura urbana y periurbana en localidades del sudeste bonaerense : posibilidades de permanencia y transformación

La Agricultura urbana y periurbana (AUP), ha crecido en Argentina junto con las crisis económicas. No es una actividad nueva, ya que en los países del continente europeo y de América del Norte se desarrollaba en tiempos de guerra o de crisis económicas. En el caso de los países de América Latina, Asia y África, la AUP muestra varios ejemplos exitosos. En Argentina, el Programa ProHuerta es tal vez la política pública más relacionada a este sector. El objetivo inicial era de autoproducción de alimentos, y hoy en día muchos de los destinatarios del programa comercializan sus productos, generando ingresos a sus hogares. El presente trabajo procuró caracterizar la agricultura urbana y periurbana surgida a partir del programa ProHuerta, en cinco localidades del sudeste bonaerense, y analizar las posibilidades de su permanencia y transformación. La metodología utilizada fue predominantemente de corte cualitativo, realizándose entrevistas en profundidad semiestructuradas y encuestas a personas que desarrollaban este tipo de actividad, así como también análisis de fuentes secundarias. Los resultados permitieron concluir que las posibilidades de permanencia dependen de varios factores, algunos relacionados con las características de las personas que realizan actividades de AUP pero también con las políticas públicas

Temporal Dynamism in Country-of-Origin Effect: The Malleability of Italians’ Perceptions Regarding the British Sixties

© Emerald Publishing Limited 2019. This accepted manuscript is deposited under the Creative Commons Attribution Non-commercial International Licence 4.0 (CC BY-NC 4.0). Any reuse is allowed in accordance with the terms outlined by the licence, here: https://creativecommons.org/licenses/by-nc/4.0/. To reuse the AAM for commercial purposes, permission should be sought by contacting [email protected]: The purpose of this paper is to enrich country of origin (COO) effect in international marketing theory by adding the understanding of temporal dynamism into COO research. Design/methodology/approach: Utilizing a qualitative and interdisciplinary phenomenological approach, this paper analyses historical and contemporary sources triangulated with contemporary primary interview data. The example of how perceptions of Italians about the values typical of the British Sixties varied over time periods is presented. Findings: COO perceptions are both malleable and in evolution. Results show that values from earlier peak periods of appeal can be combined and recombined differently over time due to the varying historical and contemporary resonances of COO values. Research limitations/implications: This study focuses on COO applied to two product areas, fashion and music, over a limited time period, in a two-country study and so the findings are not fully generalizable, but rather are transferable to similar contexts. Practical implications: The fact that COO is neither static nor atemporal facilitates a segmented approach for international marketing managers to review and renew international brands. This enriched COO theory provides a rich and variable resource for developing and revitalizing brands. Originality/value: The major contribution of this paper is that temporal dynamism, never before discussed in international marketing theory, renders COO theory more timeless; this addresses some critiques recently made about its relevance and practicality. The second contribution is the original research design that models interdisciplinary scholarship, enabling a thorough historical look at international marketing.Peer reviewe

Interface bonding of a ferromagnetic/semiconductor junction : a photoemission study of Fe/ZnSe(001)

We have probed the interface of a ferromagnetic/semiconductor (FM/SC) heterojunction by a combined high resolution photoemission spectroscopy and x-ray photoelectron diffraction study. Fe/ZnSe(001) is considered as an example of a very low reactivity interface system and it expected to constitute large Tunnel Magnetoresistance devices. We focus on the interface atomic environment, on the microscopic processes of the interface formation and on the iron valence-band. We show that the Fe contact with ZnSe induces a chemical conversion of the ZnSe outermost atomic layers. The main driving force that induces this rearrangement is the requirement for a stable Fe-Se bonding at the interface and a Se monolayer that floats at the Fe growth front. The released Zn atoms are incorporated in substitution in the Fe lattice position. This formation process is independent of the ZnSe surface termination (Zn or Se). The Fe valence-band evolution indicates that the d-states at the Fermi level show up even at submonolayer Fe coverage but that the Fe bulk character is only recovered above 10 monolayers. Indeed, the Fe 1-band states, theoretically predicted to dominate the tunneling conductance of Fe/ZnSe/Fe junctions, are strongly modified at the FM/SC interface.Comment: 23 pages, 5 figures, submitted to Physical review

Sensory profile of Italian Espresso brewed Arabica Specialty Coffee under three roasting profiles with chemical and safety insight on roasted beans

Specialty coffee (SC) has been showing an increasing interest from the consumers which appreciate its traceability and the peculiar flavours from each single origin. Additionally, the processes to which coffee fruits underwent to get green coffee characterise the beans in terms of macromolecules acting as substrates during the roasting. This work evaluates via sensory analysed eight SC, roasted at light, medium, and dark level, submitted to Italian espresso extraction, to assess how different roasting levels exalt the expected cup profile obtained by the suppliers via cupping in origin countries. Finally, roasted beans were characterised for physico-chemical features (pH, titratable acidity, caffeine, melanoidins, polyphenols and acrylamide). Sensory analysis demonstrated that the intermediate roasting level and espresso extraction match better attributes from in-origin cupping. Melanoidins (mmol g−1 coffee d.b.) was able to discriminate among roasting levels (light 0.12 ± 0.01; medium 0.13 ± 0.003; dark 0.14 ± 0.01; α = 0.05). Acrylamide analyses ensured compliance with the food safety standards (light 301.9 ± 37.2 ppb; medium 126.1±19ppb; dark 107.9 ± 22.5ppb). Physico-chemical features were able to cluster samples from different origins within the same roasting level (α = 0.05). Results showed correlations (α = 0.01) between sensory analysis and physico-chemical values: direct for caffeine and astringency, reverse for perceived acidity in relation to astringency, roasted, dried fruits and nutty notes