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Seminari  

Il Dipartimento di Fisica ospita Seminari di Dipartimento, Seminari organizzati dai gruppi di ricerca, e Physics Colloquia organizzati dalla Scuola di Dottorato.

I Seminari vengono inseriti nel Calendario.

Di seguito gli eventuali Seminari in programma nel mese in corso:

Seminari  
23/04/2018 Ore 12:30 - 14:30

Transition-metal compounds from extended Hubbard functionals

23/4/2018 ore 12:30
Dip. di Fisica, Aula Bonetti
Transition-metal compounds from extended Hubbard functionals  
Matteo Cococcioni
Theory and Simulations of Materials (THEOS), École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland

An accurate characterization and understanding of transition-metal compounds, and especially of mixed-valence compounds, is central to many advanced applications in science and technology: from battery materials to photovoltaics, from multiferroics to deep-crust minerals.
Unfortunately, first-principles approaches such as density-functional theory do not capture correctly the localization of valence electrons in low-dispersion states (e.g., d or f) and fail qualitatively and quantitatively in describing many properties of these systems.
This work shows how extended Hubbard corrections to current functionals, including on-site (U) and inter-site (V) interactions, improve dramatically the description of the electronic, magnetic and structural properties, and correctly describe localized states even in the presence of significant inter-site hybridization. Materials for Li-ion battery cathodes will be used as a test case - showing how evaluating the effective interaction parameters consistently with the electronic and crystal structures greatly improves the prediction of thermodynamic quantities and of average voltages. I will also show how to compute these interactions from density-functional perturbation theory, to ensure efficiency, accuracy and a streamlined protocol for these calculations. I will conclude with a discussion of foreseeable future developments and applications.

Locandina

INFO:
Guido Fratesi

 

20/04/2018 Ore 12:30 - 16:30

Using Poincaré half-plane to understand Crystal Elasto-Plasticity

4/20/2018 12:30:00 Dip. Fisica, Aula Caldirola
Using Poincaré half-plane to understand Crystal Elasto-Plasticity
Paolo Biscari
Dipartimento di Fisica, Politecnico di Milano

Symmetry plays a key role in establishing the mechanical response of crystalline materials.
These materials exhibit a number of peculiar features, including solid-solid phase transitions in shape memory alloys, dislocation nucleation and evolution, and critical response over several orders of magnitude. In this lecture we review how the information encoded in the lattice symmetry can be transferred to continuum models. We also show how and why the Poincaré half-plane provides a natural framework to study 2D crystal elasto-plasticity.  

http://complexitybiosystems.it/en/events/using-poincare-half-plane-to-understand-crystal-elasto-plasticity

Stefano Zapperi

stefano.zapperi@unimi.it

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