BEGIN:VCALENDAR VERSION:2.0 PRODID:-//CERN//INDICO//EN BEGIN:VEVENT SUMMARY:Classical and quantum mechanical interpretations of lossless beam splitters DTSTART;VALUE=DATE-TIME:20200926T134000Z DTEND;VALUE=DATE-TIME:20200926T140000Z DTSTAMP;VALUE=DATE-TIME:20260305T164106Z UID:indico-contribution-15-252@indico.uni.edu.pe DESCRIPTION:Speakers: Lewis Hicks (Portland State University)\nClassical a nd quantum mechanical models of a beam splitter are addressed\, including the cases where there are one or two input source(s) of light resulting in two consequent output beams. In the classical case we invoke the conserva tion of energy to derive a $2 \\times 2$ matrix $M_{bs}$ which transforms the electric fields. In the quantum mechanical case we invoke conservation of probability to show that the transformation operator $\\widehat{M}_{bs }$ from the input space to the output space must be unitary. We find that the matrix representation of $\\widehat{M}_{bs}$ in the occupation-number space is identical to the classical transformation $M_{bs}$. This formalis m is applied to describe the inner workings of a Mach-Zedner interferomete r. Additionally\, we justify the necessity of the quantum mechanical inter pretation by examining strictly quantum mechanical phenomena such as singl e-photon interference.\n\nhttps://indico.uni.edu.pe/event/85/contributions /252/ LOCATION:Lima\, Perú URL:https://indico.uni.edu.pe/event/85/contributions/252/ END:VEVENT BEGIN:VEVENT SUMMARY:Optical properties of atomically thin semiconductors: The role of excitons DTSTART;VALUE=DATE-TIME:20200926T132000Z DTEND;VALUE=DATE-TIME:20200926T134000Z DTSTAMP;VALUE=DATE-TIME:20260305T164106Z UID:indico-contribution-15-255@indico.uni.edu.pe DESCRIPTION:Speakers: Cesar E. P. Villegas (Universidad Privada del Norte (UPN))\nTwo-dimensional (2D) atom-thick crystals such as graphene\, boron- nitrade (BN)\, transition metal dichalcogenides (TMDC) and most recently phosphorus allotropes have drawn both experimental and theoretical interes t due to their unique electronic and optical properties. For instance\, T MDCs possess remarkable properties concerning the tunability of band gap a nd strong light-matter coupling that are desirable features for optoelectr onic applications. Likewise\, the phosphorus allotropes (black and blue p hosphorus) possess layered-tunable band-gap properties and a peculiar anis otropic crystalline structure\, which are important features that can be used in photonics and photovoltaics technologies. \nMotivated by this rece nt findings and considering the individual properties of the materials men tioned above\, we carry out density functional theory (DFT) calculations c ombining with the GW-Bethe-Salpeter (GW-BSE) methodology to study the exci tonic\, optical properties and the power conversion efficiency of MoTe$_{ 2}$/InN heterostructures. First\, we study the geometric and electronic s tructure of six heterostructures based on different stacking. We also ex plore the effects of the tensile strain on engineering the bandgap of the individual monolayers. Secondly\, we use the GW-BSE methodology to study the optical spectrum and estimate the power conversion efficiency of the d evice. Our results indicates that the optical band gap of the heterostruct ures are in the range of 1.12 to 1.17 eV [1]. For the sake of completenes s\, the excitonic properties of black/blue phosphorus as a function of the light-polarization are also explored [2]. We hope this work will shed som e light in the seeking of designing more efficient photovoltaics devices b ased on those materials. \nKeywords: Black phosphorus\, blue phosphorus\, optical properties\, excitons\, MoTe$_2$\n\nReferences\n[1] C.E.P. Villeg as et. al The Journal of Physical Chemistry C 119\, 11886 (2015).\n[2] C.E .P. Villegas et. al Physical Chemistry Chemical Physics 18\, 27829 (2016). \n\nhttps://indico.uni.edu.pe/event/85/contributions/255/ LOCATION:Lima\, Perú URL:https://indico.uni.edu.pe/event/85/contributions/255/ END:VEVENT BEGIN:VEVENT SUMMARY:Sensibilidad de un sensor de desplazamiento basado en fibra óptic a afinada con estructura en forma de S DTSTART;VALUE=DATE-TIME:20200926T130000Z DTEND;VALUE=DATE-TIME:20200926T132000Z DTSTAMP;VALUE=DATE-TIME:20260305T164106Z UID:indico-contribution-15-268@indico.uni.edu.pe DESCRIPTION:Speakers: Luis Mosquera Leiva (Universidad Nacional de Ingenie ría)\nPresentamos y analizamos las características de transmitancia de s ensores de desplazamiento basados en fibras ópticas monomodo afinadas y c urvadas en forma de S. Comparamos la sensibilidad del sensor de fibra afin ada curvada en S con respecto a la sensibilidad de la fibra afinada sin cu rvatura previa. Los resultados muestran sensibilidades de hasta 192 pm/µm para los sensores tipo S con respecto a sensibilidades del orden de 100 p m/µm para los sensores simplemente afinados.\n\nhttps://indico.uni.edu.pe /event/85/contributions/268/ LOCATION:Lima\, Perú URL:https://indico.uni.edu.pe/event/85/contributions/268/ END:VEVENT BEGIN:VEVENT SUMMARY:Manipulation of spin currents with synthetic antferromagnets DTSTART;VALUE=DATE-TIME:20200924T190000Z DTEND;VALUE=DATE-TIME:20200924T192000Z DTSTAMP;VALUE=DATE-TIME:20260305T164106Z UID:indico-contribution-15-237@indico.uni.edu.pe DESCRIPTION:Speakers: Luis Aviles Felix (Centro Atómico Bariloche - CNEA Argentina)\nThe adaptability of synthetic antiferromagnets (SAF) in spintr onic devices based on spin Hall effects has emerged during the last years. In this work we report the use of a SAF (antiferromagnetically exchange c oupled Co/Ru/Co) as a spin current injector and the observation of spin pu mping and inverse spin Hall effect in [SAF]/Pt heterostructures [1\,2]. By exploiting the interlayer exchange coupling strength (oscillatory RKKY-li ke coupling) and the spin-flop transition in the magnetization process of the SAF it is possible to rotate the magnetization of the Co layers at giv en angles away from the external magnetic field direction in resonance con dition. The misalignment due to the spin-flop magnetization process combin ed with the spin pumping and the inverse spin Hall effect\, allow to contr ol and detect the polarization direction of the spin current pumped into t he Pt. The control of the polarization direction of the spin current was a lso achieved by controlling the interlayer exchange coupling (IEC) via var iations in the Ru spacer in the SAF-Pt system. By controlling the IEC stre ngth and the spin flop transition in the magnetization process\, it is als o possible to produce spin currents polarized in different directions. Our results can lead to important advances in hybrid spintronic devices with improved functionalities\, particularly the ability to control the polariz ation direction of spin currents and also the change of the sign of the in verse spin Hall effect signal induced in a metallic layer with the strong spin-orbit interaction.\n\nhttps://indico.uni.edu.pe/event/85/contribution s/237/ LOCATION:Lima\, Perú URL:https://indico.uni.edu.pe/event/85/contributions/237/ END:VEVENT BEGIN:VEVENT SUMMARY:Low-temperature quantum transport in semiconductor/superconductor devices DTSTART;VALUE=DATE-TIME:20200924T200000Z DTEND;VALUE=DATE-TIME:20200924T203000Z DTSTAMP;VALUE=DATE-TIME:20260305T164106Z UID:indico-contribution-15-245@indico.uni.edu.pe DESCRIPTION:Speakers: Juan Carlos Estrada Saldaña (University of Copenhag en)\nI will show concluded and current experimental work done at the Cente r for Quantum Devices\, Copenhagen [1\,2] and at CEA\, Grenoble [3\,4]. Th e work is based on electrical measurements at (sub-Kelvin) dilution-refrig erator temperatures on devices based on individual semiconductor nanowires with epitaxially-grown superconductors. Single electron spins can be conf ined in the nanowires\, and their influence on the superconductors can be studied through their effect on the Josephson supercurrent and the discret e excitations within the superconducting gap.\n\nReferences:\n1. Estrada S aldaña\, J. C.\, Vekris\, A.\, Sosnovtseva\, V.\, Kanne\, T.\, Krogstrup\ , P.\, Grove-Rasmussen\, K.\, & Nygård\, J. (2020). Temperature induced s hifts of Yu–Shiba–Rusinov resonances in nanowire-based hybrid quantum dots. Commun. Phys.\, 3(125)\, 1–11.\n2. Estrada Saldaña\, J. C.\, Vekr is\, A.\, Steffensen\, G.\, Žitko\, R.\, Krogstrup\, P.\, Paaske\, J.\, G rove-Rasmussen\, K.\, and Nygård\, J. (2018). Supercurrent in a Double Qu antum Dot. Phys. Rev. Lett.\, 121(25)\, 257701.\n3. Estrada Saldaña\, J. C.\, Žitko\, R.\, Cleuziou\, J. P.\, Lee\, E. J. H.\, Zannier\, V.\, Erco lani\, D.\, Sorba\, L.\, Aguado\, R.\, De Franceschi\, S. (2019). Charge l ocalization and reentrant superconductivity in a quasi-ballistic InAs nano wire coupled to superconductors. Sci. Adv.\, 5(7)\, eaav1235.\n4. Estrada Saldaña\, J. C.\, Niquet\, Y.-M.\, Cleuziou\, J.-P.\, Lee\, E. J. H.\, Ca r\, D.\, Plissard\, S.\, Bakkers\, E.P.A.M. De Franceschi\, S. (2018). Spl it-Channel Ballistic Transport in an InSb Nanowire. Nano Lett.\, 18(4)\, 2 282–2287. \n\nThe project received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska -Curie grant agreement No. 832645.\n\nhttps://indico.uni.edu.pe/event/85/c ontributions/245/ LOCATION:Lima\, Perú URL:https://indico.uni.edu.pe/event/85/contributions/245/ END:VEVENT BEGIN:VEVENT SUMMARY:Magnetic properties of the series YFexCr1-xO3 DTSTART;VALUE=DATE-TIME:20200926T203000Z DTEND;VALUE=DATE-TIME:20200926T210000Z DTSTAMP;VALUE=DATE-TIME:20260305T164106Z UID:indico-contribution-15-270@indico.uni.edu.pe DESCRIPTION:Speakers: Roberto Salazar-Rodriguez (Universidad Nacional de I ngeniería)\nDue to their interest in both experimental and theoretical st udy of the structural and electronic properties as multiferroic materials\ , the compounds YFexCr1-xO3 (x = 0.25\, 0.50\, 0.75 and 1) were prepared b y autocombustion. They were analyzed using techniques that provide informa tion both at the atomic and macroscopic level\, including low temperature neutron diffraction\, 57Fe Mössbauer spectrometry under external magnetic field and magnetic hysteresis loops. It is concluded that\, although thes e compounds can be structurally described as solid solutions resulting fro m distorted octahedra of FeO6 and CrO6 supported by an orthorhombic struct ure\, the magnetic properties are not colinear. Indeed\, for example\, the central compound (x = 0.50) is a canted weak antiferromagnetic (WAF) with a ferromagnetic saturation moment even higher than that of YFeO3. This be havior seems to be linked to the fact that it is a very thermally stable m aterial (the lattice parameters a\, b and c do not change when the tempera ture drops). Moreover\, the description of the Mössbauer spectra under ap plied field gives rise to canted antiferromagnetic structures. These resul ts are very interesting and encourage more work in this system.\n\nhttps:/ /indico.uni.edu.pe/event/85/contributions/270/ LOCATION:Lima\, Perú URL:https://indico.uni.edu.pe/event/85/contributions/270/ END:VEVENT BEGIN:VEVENT SUMMARY:Spin-orbit phenomena in graphene-based spin devices DTSTART;VALUE=DATE-TIME:20200924T203000Z DTEND;VALUE=DATE-TIME:20200924T210000Z DTSTAMP;VALUE=DATE-TIME:20260305T164106Z UID:indico-contribution-15-284@indico.uni.edu.pe DESCRIPTION:Speakers: Williams Savero Torres (1Catalan Institute of Nanosc ience and Nanotechnology (ICN2)\, CSIC and the Barcelona Institute of Scie nce and Technology (BIST)\, Barcelona\, Spain)\nTwo dimensional materials have provided unique insights in condensed matter physics\, yielding a mul titude of novel effects. Among them\, graphene has shown to be an outstand ing material owing to its exceptional and tunable electrical properties. I n graphene\, spin information can propagate over long distances and also b e manipulated by proximity induced phenomena [1\,2\,3]\, providing thus th e building blocks for developing graphene-based spintronic devices.\n\nIn this talk\, I will discuss recent spin transport experiments in van der Wa als heterostructures consisting of graphene and transition metal dichalcog enides. First\, I will describe how proximity induced spin-orbit effects l ead to an anisotropic spin dynamics in graphene and enable to manipulate s pin transport. In the second part\, I will show how spin-orbit proximity e ffects can induce an efficient generation and detection of spin currents\, that is comparable to the largest reported to date. These findings provid e a novel route for spin generation free from magnetic materials and pave the way for the development of ultra-compact and low power consumption mag netic memory devices. \n\n\n[1] W. Han et al. Nat. Nano. 9 974\, (2014)\n [2] W. Savero Torres et al. MRS Bulletin 45(5)\, 357-365\, (2020)\n[3] W. Savero Torres et al. 2D Mat. 4\, 041008\, (2017)\n[4] L. A. Benítez\, J.F . Sierra\, W. Savero Torres et al. Nat. Phys. 14\, 303-308\, (2018)\n[5] L . A. Benítez\, W. Savero Torres et al. Nat. Mat. 19\, 170-175\, (2020)\n\ nhttps://indico.uni.edu.pe/event/85/contributions/284/ LOCATION:Lima\, Perú URL:https://indico.uni.edu.pe/event/85/contributions/284/ END:VEVENT BEGIN:VEVENT SUMMARY:Cálculos ab-initio para el estudio de las propiedades estructural es\, magnéticas e hiperfinas del sistema MgFe2O4 DTSTART;VALUE=DATE-TIME:20200924T194000Z DTEND;VALUE=DATE-TIME:20200924T200000Z DTSTAMP;VALUE=DATE-TIME:20260305T164106Z UID:indico-contribution-15-249@indico.uni.edu.pe DESCRIPTION:Speakers: Arles V. Gil Rebaza (Instituto de Física La Plata I FLP-CONICET\, Universidad Nacional de La Plata\, La Plata - Argentina.)\nL as ferritas (MFe2O4) son una de las familias de materiales magnéticos má s estudiados tanto desde el punto de vista básico como aplicado. Las ferr itas cristalizan en la estructura espinela y poseen dos sitios para los ca tiones\, A y B. Esta característica hace que sus propiedades magnéticas de estos óxidos dependan de la distribución de cationes en las subredes de sitios A y B. El acoplamiento magnético entre los cationes es de super intercambio vía mediación con los oxígenos\, dando como resultado acopl amientos A-O-A (JAA)\, B-O-B (JBB) y A-O-B (JAB)\, donde A y B representan los sitios estructurales. En los casos en que M es un metal no magnético (Zn\, Ti\, etc.) y los Fe ocupan sólo los sitios B (estructura normal) únicamente se presentan débiles interacciones B-O-B\, lo que da lugar a bajas temperaturas de orden. Dado que los Fe forman una red tipo pirocloro con frustración geométrica más el desorden de espín en la subred de s itios B el estado fundamental es altamente degenerado\, pudiendo presentar se ordenamientos magnéticos antiferromagnéticos\, ferrimagnéticos o de tipo vidrio de espín a bajas temperaturas. A medida que el número de ion es Fe en sitios A se incrementa se producen cambios en la interacción Fe- Fe y por ende en la respuesta magnética del sistema. En el presente traba jo\, reportamos los resultados del estudio de las propiedades estructurale s\, magnéticas e hiperfinas de la ferrita de Mg\, MgFe2O4 a partir de cá lculos de primeros principios basados en la Teoría de la Funcional Densid ad (DFT) y el método Full Potential - Linearized Augmented PlaneWave (FP- LAPW). Esta ferrita se reporta como invertida (sitios A ocupados por Fe y los B por Fe y Mn en igual proporción). Con el fin de determinar el estad o fundamental estructural y magnético exploramos sistemas con diferentes grados de inversión catiónica\, distribución de iones Mg y Fe en la sub red de sitios A y B y diferentes configuraciones magnéticas.\n\nhttps://i ndico.uni.edu.pe/event/85/contributions/249/ LOCATION:Lima\, Perú URL:https://indico.uni.edu.pe/event/85/contributions/249/ END:VEVENT BEGIN:VEVENT SUMMARY:Obtención del Hamiltoniano magnético a partir de espectroscopia Mössbauer y difracción de rayos X de la composición AlxFe(1-x) (x=0\ ,25\;0\,5\;0\,75) obtenida por molienda mecánica DTSTART;VALUE=DATE-TIME:20200924T192000Z DTEND;VALUE=DATE-TIME:20200924T194000Z DTSTAMP;VALUE=DATE-TIME:20260305T164106Z UID:indico-contribution-15-242@indico.uni.edu.pe DESCRIPTION:Speakers: Ronald David Rocha Cabrera (UNMSM)\nEn el presente t rabajo\, a partir del estudio estructural y magnético de la aleación Alx Fe(1-x) con x=0\,25\; 0\,5 y 0\,75\, se plantea el Hamiltoniano magnétic o. Primero las muestras fueron sintetizadas por la técnica de horno de ar co (HA) y posteriormente fueron tratadas a las temperaturas de 600 C\, 950 C y 1000C por 48\, 290 y 48 horas respectivamente. Después del tratamient o térmico correspondiente a la temperatura de 600C\, las muestras fueron nanoestructuradas por la técnica de molienda mecánica (MM)\, el estudio estrcutural y magnético fue realizado por las técnicas de difracción d e rayos X (DRX) y espectroscopia Mössbauer (SM)\, a partir del cual se p lantea el Hamiltoniano\, el cual tiene diferente comportamiento para cada composición. Para la composición Al25Fe75 y Al50Fe50 ferromagnética y p aramagnética\, durante el proceso de nanoestructuración se observa la fo rmación de la maghemita Fe2O3(Al)\, además de la solución sólida Fe(Al ) rica y pobre en hierro. Para la composición Al75Fe25\, nanoestructurada \, se observa la formación del intermetálico Al13Fe4 y la solución só lida Fe(Al)\, ambos paramagnéticos [1].\n\n**Palabras claves:** Espectros copia Mössbauer\, Difracción de rayos X \, Horno de arco\, molienda mec ánica\, Hamiltoniano.\n\n**Referencia:** \n[1] V. A. Peña Rodríguez\, J . Medina Medina\, J. Quispe Marcatoma\, Ch. Rojas Ayala\, C. V. Landauro\, E. M. Baggio-Saitovitch E. C. Passamani\, Hyperfine Interact.\, 202\, 145 (2011).\n\nhttps://indico.uni.edu.pe/event/85/contributions/242/ LOCATION:Lima\, Perú URL:https://indico.uni.edu.pe/event/85/contributions/242/ END:VEVENT END:VCALENDAR