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El límit per poder anunciar en paper seminaris i conferències en els ascensors és el divendres a les 12 hores de la setmana anterior. Amb posterioritat a aquesta data el seminari o conferència quedarà només recollit al web de la Facultat. Aleshores la publicitació en paper serà responsabilitat dels organitzadors.



Facultat de Física, Dijous 25 de Abril de 2019, a les 12:00h

Seminari de l'Institut de Nanociència i Nanotecnologia

Títol: Energy Loss Spectroscopy at High Resolution: Probing the local electronic structure and the plasmonic respons
Conferenciant: Prof. Dr. Gianluigi Botton, Department of Materials Science and Engineering and Canadian Centre for Electron Microscopy, McMaster University, Hamilton, Canada
Abstract:

Electron energy loss spectroscopy (EELS) is an invaluable technique to study the detailed structure and the chemical state of materials at unprecedented spatial resolution. This technique, combined with aberration-corrected microscopes, is used to characterize nanoscale materials used in a myriad of applications from energy storage and conversion, to solid-state devices and biomaterials interfaces.

In this presentation, recent developments in EELS to probe the changes in bonding and coordination of atoms will be described. It will also be shown that, with aberration-corrected and atomic resolved EELS, it is possible to determine ordering of cations in oxides and changes in bonding at interfaces. It will be highlighted how atomic resolved experiments with EELS near edge fine structures can be used to systematically study the local valence in high-T superconductors and even prove the local electronic structure of energy storage materials.
 
Finally, it will also be shown how EELS can provide exquisite details on the plasmonic response of simple and very complex metallic nanostructures.

Lloc: Enric Casassas
Contacte: isaborit@ub.edu
Web: http://www.ub.edu/in2ub/files/IN2UB_IRS_25.04.2019.pdf

Facultat de Física, Dijous 25 de Abril de 2019, a les 14:00h

Seminari de l'Institut de Ciències del Cosmos

Títol: Lie Algebra Expansions and Actions for Non-Relativistic Gravity
Conferenciant: Eric Bergshoeff
Abstract:

We show that the general method of Lie algebra expansions can be applied to re-construct several algebras and related actions for non-relativistic gravity that have occurred in the recent literature. We explain the method and illustrate its applications by giving several explicit examples. The method can be generalized to include the construction of actions or ultra-relativistic gravity, i.e.~Carroll gravity, and non-relativistic supergravity as well.

Lloc: Aula 507 (Pere Pascual)
Contacte: secretariacientifica@icc.ub.edu
Web: http://icc.ub.edu/activity/1342

Facultat de Física, Dijous 25 de Abril de 2019, a les 9.00h

Seminari de l'Institut de Nanociència i Nanotecnologia

Títol: Recent Advances in Spintronics
Conferenciant: Prof. Fèlix Casanova (CIC nanoGUNE Donostia)
Abstract:

The integration of the spin degree of freedom in charge-based electronic devices has already revolutionized both sensing and memory capability in microelectronics. A second generation of devices is now envisioned in which pure spin currents (a diffusive flow of spins with no net charge flow) could be used instead, with several proposals that advance towards the integration of spin logics and memory. This could represent a post-CMOS paradigm in electronics with faster data processing speed, non-volatility and lower power consumption, with its enormous social and economic impact.

In this tutorial, which will be divided in two sessions, we will overview the concept of pure spin currents and how they can be i) generated/detected, ii) transported and iii) manipulated, which are the key ingredients for a functional spintronic device.

During the first session (9.00-9.50h), we will introduce the basic concepts to understand pure spin currents (two-current model, spin accumulation); explain electrical spin injection using ferromagnetic materials, one of the first and most used mechanisms of spin generation; discuss the mechanisms of spin transport in different materials; and review different approaches to manipulate spin currents (Hanle effect, Rashba effect). Finally, I will discuss some spin-based logic proposals.

During the second session (10.00-10.50h), we will focus on the spin Hall effect (SHE), which is a very relevant alternative to generate/detect pure spin currents. We will explain the different mechanisms giving rise to SHE and the relation with the well-known anomalous Hall effect; the different techniques used to quantify SHE; novel spin-dependent phenomena discovered by using SHE (such as spin pumping and spin Seebeck effect); and other spin-orbit coupling effects (Edelstein effect in interfaces and topological surfaces) that also allows spin-charge interconversion. Finally, I will discuss potential applications (spin-orbit torques, spin-orbit-based logic).


Short Bio:
Fèlix Casanova is an Ikerbasque Research Professor at CIC nanoGUNE (Basque Country). He obtained his Ph.D. in Physics from Universitat de Barcelona in 2004 with a study of the magnetocaloric effect. He was a postdoctoral researcher at the University of California, San Diego from 2005 to 2009, where he worked in a variety of projects in nanoscience, including nanoporous materials and spintronics in metals, and he acquired extensive experience in nanofabrication techniques. Since 2009, he is the coleader of the Nanodevices Group at CIC nanoGUNE, devoted to the electronic properties of systems in reduced dimensions. His current research interests are focused on spin-dependent phenomena (including spin transport and spin-orbit effects) in metals, insulators and novel two-dimensional materials. His pioneering studies on spin-charge interconversion in metals have led to an R+D contract with Intel Corp., the world-leading microelectronics company. He is Editorial Board member of Physical Review Applied, published by the APS.


Contact: Xavier Batlle (xavierbatlle@ub.edu)

This talk has been funded by the Master in Nanoscience and Nanotechnology of the UB.

Lloc: Room 325 (3th Floor Faculty of Physics, New Building)
Contacte: xavierbatlle@ub.edu
Web:

Facultat de Física, Divendres 26 de Abril de 2019, a les 12:00h

Seminari de l'Institut de Ciències del Cosmos

Títol: The large D membrane paradigm for general four-derivative theory of gravity in the presence of a cosmological
Conferenciant: Taniya Mandal
Abstract:

The large D membrane paradigm defines an equivalence between black hole dynamics and the dynamics of a membrane propagating in a spacetime to which the black hole asymptotes to. In this talk I will discuss the large D membrane paradigm for the most general theory of four-derivative gravity in the presence of a negative cosmological constant. I will limit the discussion to linearised order in the parameter determining the strength of the four-derivative coupling.

Lloc: Aula 507 (Pere Pascual)
Contacte: secretariacientifica@icc.ub.edu
Web: http://icc.ub.edu/activity/1343

Facultat de Física, de Dilluns 29 de Abril de 2019 a Dilluns 01 de Juliol de 2019, a les 11 - h

Curs de la Facultat de Física

Títol: Stochastic Modelling of Transport in Heterogeneous Media
Conferenciant: Marco Dentz / Juan Hidalgo (IDAEA-CSIC)
Abstract:

Postgraduate course for physicists, chemists and engineers.
Organized in five 2-hour sessions, on Monday:
- April 29: Introduction to transport in heterogeneous media.
- May 13: Langevin and Fokker-Planck equations
- May 20: Dispersion
- June 3: Continuous time random walks
- July 1: Trapping models

Lloc: Aula 3.20 (planta 3 Fisica UB part nova)
Contacte: jordi.ortin@ub.edu
Web:

Facultat de Física, Dimarts 30 de Abril de 2019, a les 12:00h

Seminari de l'Institut de Ciències del Cosmos

Títol: Exploring the GAIA view of High-Mass X-ray Binaries
Conferenciant: Sylvain Chaty, Francis Fortin, Federico García
Abstract:

High mass X-ray binaries (HMXBs) are binary systems formed by a compact object, either a black hole (BH) or a neutron star (NS), which accretes matter from a high-mass stellar companion. After the detection of gravitational waves originated in compact object mergers, HMXBs have gained new attraction as they are thought to be part of their progenitors. Recently, the second GAIA Data Release was published, containing 1.7 billion stars for which for about 76% of them, a 5D astrometric solution was obtained, including position, parallax and proper motion.
We used this information to study their velocities and we found that a significant fraction of the HMXB population shows a high peculiar velocity, incompatible with Galactic rotation.

Lloc: Aula 507 (Pere Pascual)
Contacte: secretariacientifica@icc.ub.edu
Web: http://icc.ub.edu/activity/1330