First-principles theory of flexoelectricity: methods and applications

by Andrea Schiaffino, Theory and Simulations Group, ICMAB-CSIC

Date: Tuesday, 2 July 2019
Time: 11 am
Venue: Sala d'actes Carles Miravitlles, ICMAB-CSIC

Andrea and his sailing boat (photo: Carlos Frontera)

Abstract: This thesis is focused on the microscopic theoretical description of flexoelectricity that is the universal  property of insulators of developing a polar response to a uniform strain gradient perturbation. The first part of the presentation will cover the most recent developments concerning the calculation of the bulk flexoelectric tensor by using density functional theory, with major emphasis on introducing the original concept of the metric-wave perturbation in crystals.In the second part, the effects of flexoelectricity in two concrete physical systems are discussed. First, the feasibility of engineering the flexoelectric response to enhance the photovoltaic performance of single crystals (flexovoltaic) is discussed; second, the origin of the polarity at the ferroelastic domain walls in SrTiO3 is analyzed using an effective model.

Supervisor:

• Dr. Massimiliano Stengel, ICREA Research Professor, ICMAB-CSIC

PhD Committee:

• President: Dr. Ivo Souza, Centro de Física de Materiales, Universidad del País Vasco, Ikerbasque Foundation, Spain
• Secretary: Dr. Gustau Catalan, Institut Català de Nanociència i Nanotecnologia (ICN2), Spain
• Vocal: Dr. Raffaele Resta, Istituto Officina dei Materiali, CNR (Trieste), Italy

Celebrating the thesis after the defense.